My server keeps crashing!!

My server keeps crashing and I don't know why. It kicks all players and says Server Closed and actually stops even when only 1 person logs on. Here are my plugins: ArchonCrates AutoAnnouncer Buycraft Clearlagg CustomEnchantments Essentials EssentailsGeoip EssentialsXXMP Kitpreview Massivecore MassivecoreFactions mcMMO MythicMobs ObsidianBreaker PermissionsEx PluginMatrics SilkSpawners PlayerVaults Timelock Updater Vault Worldedit WorldGuard. Here is my latest crash report:

Code:

---- Minecraft Crash Report ----
// Hi. I'm Minecraft, and I'm a crashaholic.

Time: 10/4/15 7:53 AM
Description: Ticking block entity

java.lang.NullPointerException: Ticking block entity
    at net.minecraft.server.v1_8_R1.TileEntity.getOwner(TileEntity.java:190)
    at net.minecraft.server.v1_8_R1.TileEntityHopper.r(TileEntityHopper.java:262)
    at net.minecraft.server.v1_8_R1.TileEntityHopper.m(TileEntityHopper.java:188)
    at net.minecraft.server.v1_8_R1.TileEntityHopper.c(TileEntityHopper.java:176)
    at net.minecraft.server.v1_8_R1.World.tickEntities(World.java:1267)
    at net.minecraft.server.v1_8_R1.WorldServer.tickEntities(WorldServer.java:539)
    at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:715)
    at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:284)
    at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:609)
    at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:517)
    at java.lang.Thread.run(Unknown Source)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
    at net.minecraft.server.v1_8_R1.TileEntity.getOwner(TileEntity.java:190)
    at net.minecraft.server.v1_8_R1.TileEntityHopper.r(TileEntityHopper.java:262)
    at net.minecraft.server.v1_8_R1.TileEntityHopper.m(TileEntityHopper.java:188)
    at net.minecraft.server.v1_8_R1.TileEntityHopper.c(TileEntityHopper.java:176)

-- Block entity being ticked --
Details:
    Name: Hopper // net.minecraft.server.v1_8_R1.TileEntityHopper
    Block type: ID #154 (tile.hopper // net.minecraft.server.v1_8_R1.BlockHopper)
    Block data value: 5 / 0x5 / 0b0101
    Block location: World: (-2019,68,-68), Chunk: (at 13,4,12 in -127,-5; contains blocks -2032,0,-80 to -2017,255,-65), Region: (-4,-1; contains chunks -128,-32 to -97,-1, blocks -2048,0,-512 to -1537,255,-1)
    Actual block type: ID #154 (tile.hopper // net.minecraft.server.v1_8_R1.BlockHopper)
    Actual block data value: 5 / 0x5 / 0b0101
Stacktrace:
    at net.minecraft.server.v1_8_R1.World.tickEntities(World.java:1267)
    at net.minecraft.server.v1_8_R1.WorldServer.tickEntities(WorldServer.java:539)

-- Affected level --
Details:
    Level name: map_the_end
    All players: 1 total; [EntityPlayer['johnny97mcc'/393, l='map_the_end', x=-2020.21, y=68.00, z=-67.39](johnny97mcc at -2020.2064115448507,68.0,-67.39153858689049)]
    Chunk stats: ServerChunkCache: 289 Drop: 0
    Level seed: -1908965162636695094
    Level generator: ID 00 - default, ver 1. Features enabled: true
    Level generator options: 
    Level spawn location: 0.00,0.00,0.00 - World: (0,0,0), Chunk: (at 0,0,0 in 0,0; contains blocks 0,0,0 to 15,255,15), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
    Level time: 53129021 game time, 92214007 day time
    Level dimension: 0
    Level storage version: 0x04ABD - Anvil
    Level weather: Rain time: 0 (now: false), thunder time: 0 (now: false)
    Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
    at net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:715)
    at net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:284)
    at net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:609)
    at net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:517)
    at java.lang.Thread.run(Unknown Source)

-- System Details --
Details:
    Minecraft Version: 1.8
    Operating System: Linux (amd64) version 3.14.32-xxxx-std-ipv6-64-hz1000
    Java Version: 1.7.0_80, Oracle Corporation
    Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
    Memory: 387255088 bytes (369 MB) / 643489792 bytes (613 MB) up to 2075918336 bytes (1979 MB)
    JVM Flags: 21 total; -Xincgc -XX:+UseParNewGC -XX:MaxPermSize=256M -XX:NewRatio=2 -XX:CMSFullGCsBeforeCompaction=1 -XX:+UseConcMarkSweepGC -XX:SoftRefLRUPolicyMSPerMB=2048 -XX:+CMSParallelRemarkEnabled -XX:+UseAdaptiveSizePolicy -XX:+DisableExplicitGC -Xnoclassgc -Xoss4M -Xss4M -XX:+UseFastAccessorMethods -XX:CMSInitiatingOccupancyFraction=90 -XX:UseSSE=4 -XX:+UseCMSCompactAtFullCollection -XX:ParallelGCThreads=4 -XX:+AggressiveOpts -Xmx2048M -Xms512M
    IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
    CraftBukkit Information: 
   Running: CraftBukkit version git-Bukkit-33d5de3 (MC: 1.8) (Implementing API version 1.8-R0.1-SNAPSHOT) true
   Plugins: { ObsidianBreaker v2.1 com.creeperevents.oggehej.obsidianbreaker.ObsidianBreaker [oggehej], WorldEdit v6.1;no_git_id com.sk89q.worldedit.bukkit.WorldEditPlugin [], Buycraft v6.8.1 net.buycraft.Plugin [Tebex Limited], MassiveCore v2.8.0 com.massivecraft.massivecore.MassiveCore [Cayorion], TimeLock v0.5 me.speed.timelock.TimeLock [SPEED], Vault v1.5.6-b49 net.milkbowl.vault.Vault [cereal, Sleaker, mung3r], ClearLag v2.8.2 me.minebuilders.clearlag.Clearlag [bob7l], PermissionsEx v1.23.3 ru.tehkode.permissions.bukkit.PermissionsEx [[t3hk0d3, zml]], PlayerVaults v3.5.7-b${BUILD_NUMBER} com.drtshock.playervaults.PlayerVaults [drtshock, Koalaaaa], mcMMO v1.5.00-b3547 com.gmail.nossr50.mcMMO [nossr50, GJ, NuclearW, bm01, Glitchfinder, TfT_02, t00thpick1, Riking], WorldGuard v6.1 com.sk89q.worldguard.bukkit.WorldGuardPlugin [], AutoAnnouncer v1.7-03.23 com.sectorgamer.sharkiller.AutoAnnouncer.Announcer [Sharkiller], Essentials vTeamCity com.earth2me.essentials.Essentials [Zenexer, ementalo, Aelux, Brettflan, KimKandor, snowleo, ceulemans, Xeology, KHobbits, md_5, Iaccidentally], SilkSpawners v3.6.7 de.dustplanet.silkspawners.SilkSpawners [xGhOsTkiLLeRx, mushroomhostage], EssentialsXMPP vTeamCity com.earth2me.essentials.xmpp.EssentialsXMPP [snowleo], ArchonCrates v15.0 com.HamiStudios.ArchonCrates.Main [], EssentialsProtect vTeamCity com.earth2me.essentials.protect.EssentialsProtect [Zenexer, ementalo, Aelux, Brettflan, KimKandor, snowleo, ceulemans, Xeology, KHobbits], EssentialsSpawn vTeamCity com.earth2me.essentials.spawn.EssentialsSpawn [Zenexer, ementalo, Aelux, Brettflan, KimKandor, snowleo, ceulemans, Xeology, KHobbits], EssentialsGeoIP vTeamCity com.earth2me.essentials.geoip.EssentialsGeoIP [Zenexer, ementalo, Aelux, Brettflan, KimKandor, snowleo, ceulemans, Xeology], EssentialsChat vTeamCity com.earth2me.essentials.chat.EssentialsChat [Zenexer, ementalo, Aelux, Brettflan, KimKandor, snowleo, ceulemans, Xeology, KHobbits, md_5, Okamosy, Iaccidentally], KitAdder v2.2 kitadder.KitAdder [], EssentialsAntiBuild vTeamCity com.earth2me.essentials.antibuild.EssentialsAntiBuild [Zenexer, ementalo, Aelux, Brettflan, KimKandor, snowleo, ceulemans, Xeology, KHobbits, Iaccidentally], KitPreview v0.1.3 me.regablith.kitpreview.Core [Regablith], Factions v2.8.0 com.massivecraft.factions.Factions [Cayorion, Brettflan],}
   Warnings: DEFAULT
   Reload Count: 0
   Threads: { TIMED_WAITING process reaper: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source), java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(Unknown Source), java.util.concurrent.SynchronousQueue$TransferStack.transfer(Unknown Source), java.util.concurrent.SynchronousQueue.poll(Unknown Source), java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source), java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source), java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source), java.lang.Thread.run(Unknown Source)], RUNNABLE Netty Server IO #1: [sun.nio.ch.EPollArrayWrapper.epollWait(Native Method), sun.nio.ch.EPollArrayWrapper.poll(Unknown Source), sun.nio.ch.EPollSelectorImpl.doSelect(Unknown Source), sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source), sun.nio.ch.SelectorImpl.select(Unknown Source), io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:618), io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:306), io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116), java.lang.Thread.run(Unknown Source)], WAITING Chunk I/O Executor Thread-1: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.park(Unknown Source), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source), java.util.concurrent.LinkedBlockingQueue.take(Unknown Source), java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source), java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source), java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source), java.lang.Thread.run(Unknown Source)], TIMED_WAITING Server Infinisleeper: [java.lang.Thread.sleep(Native Method), net.minecraft.server.v1_8_R1.ThreadSleepForever.run(SourceFile:64)], RUNNABLE Server console handler: [java.io.FileInputStream.readBytes(Native Method), java.io.FileInputStream.read(Unknown Source), java.io.BufferedInputStream.fill(Unknown Source), java.io.BufferedInputStream.read(Unknown Source), org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.read(NonBlockingInputStream.java:169), org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.read(NonBlockingInputStream.java:137), org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.read(NonBlockingInputStream.java:246), org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader.read(InputStreamReader.java:261), org.bukkit.craftbukkit.libs.jline.internal.InputStreamReader.read(InputStreamReader.java:198), org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.readCharacter(ConsoleReader.java:2145), org.bukkit.craftbukkit.libs.jline.console.ConsoleReader.readLine(ConsoleReader.java:2349), net.minecraft.server.v1_8_R1.ThreadCommandReader.run(ThreadCommandReader.java:33)], RUNNABLE Signal Dispatcher: [], TIMED_WAITING Timer-0: [java.lang.Object.wait(Native Method), java.util.TimerThread.mainLoop(Unknown Source), java.util.TimerThread.run(Unknown Source)], WAITING pool-20-thread-1: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.park(Unknown Source), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source), java.util.concurrent.LinkedBlockingQueue.take(Unknown Source), java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source), java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source), java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source), java.lang.Thread.run(Unknown Source)], WAITING Thread-5: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.park(Unknown Source), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source), java.util.concurrent.LinkedBlockingQueue.take(Unknown Source), com.mojang.util.QueueLogAppender.getNextLogEvent(QueueLogAppender.java:77), org.bukkit.craftbukkit.v1_8_R1.util.TerminalConsoleWriterThread.run(TerminalConsoleWriterThread.java:25), java.lang.Thread.run(Unknown Source)], TIMED_WAITING pool-19-thread-1: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(Unknown Source), java.util.concurrent.LinkedBlockingDeque.pollFirst(Unknown Source), java.util.concurrent.LinkedBlockingDeque.poll(Unknown Source), java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source), java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source), java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source), java.lang.Thread.run(Unknown Source)], WAITING Finalizer: [java.lang.Object.wait(Native Method), java.lang.ref.ReferenceQueue.remove(Unknown Source), java.lang.ref.ReferenceQueue.remove(Unknown Source), java.lang.ref.Finalizer$FinalizerThread.run(Unknown Source)], WAITING Reference Handler: [java.lang.Object.wait(Native Method), java.lang.Object.wait(Object.java:503), java.lang.ref.Reference$ReferenceHandler.run(Unknown Source)], TIMED_WAITING Timer-1: [java.lang.Object.wait(Native Method), java.util.TimerThread.mainLoop(Unknown Source), java.util.TimerThread.run(Unknown Source)], RUNNABLE DestroyJavaVM: [], TIMED_WAITING MStore ExamineThread: [java.lang.Thread.sleep(Native Method), com.massivecraft.massivecore.store.ExamineThread.run(ExamineThread.java:55)], WAITING Java2D Disposer: [java.lang.Object.wait(Native Method), java.lang.ref.ReferenceQueue.remove(Unknown Source), java.lang.ref.ReferenceQueue.remove(Unknown Source), sun.java2d.Disposer.run(Unknown Source), java.lang.Thread.run(Unknown Source)], WAITING NonBlockingInputStreamThread: [java.lang.Object.wait(Native Method), org.bukkit.craftbukkit.libs.jline.internal.NonBlockingInputStream.run(NonBlockingInputStream.java:278), java.lang.Thread.run(Unknown Source)], WAITING pool-5-thread-2: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.park(Unknown Source), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source), java.util.concurrent.LinkedBlockingQueue.take(Unknown Source), java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source), java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source), java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source), java.lang.Thread.run(Unknown Source)], TIMED_WAITING pool-3-thread-1: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source), java.util.concurrent.SynchronousQueue$TransferStack.awaitFulfill(Unknown Source), java.util.concurrent.SynchronousQueue$TransferStack.transfer(Unknown Source), java.util.concurrent.SynchronousQueue.poll(Unknown Source), java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source), java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source), java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source), java.lang.Thread.run(Unknown Source)], WAITING pool-5-thread-1: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.park(Unknown Source), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source), java.util.concurrent.LinkedBlockingQueue.take(Unknown Source), java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source), java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source), java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source), java.lang.Thread.run(Unknown Source)], RUNNABLE Netty Server IO #0: [sun.nio.ch.EPollArrayWrapper.epollWait(Native Method), sun.nio.ch.EPollArrayWrapper.poll(Unknown Source), sun.nio.ch.EPollSelectorImpl.doSelect(Unknown Source), sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source), sun.nio.ch.SelectorImpl.select(Unknown Source), io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:618), io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:306), io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116), java.lang.Thread.run(Unknown Source)], WAITING pool-5-thread-3: [sun.misc.Unsafe.park(Native Method), java.util.concurrent.locks.LockSupport.park(Unknown Source), java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source), java.util.concurrent.LinkedBlockingQueue.take(Unknown Source), java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source), java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source), java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source), java.lang.Thread.run(Unknown Source)], TIMED_WAITING File IO Thread: [java.lang.Thread.sleep(Native Method), net.minecraft.server.v1_8_R1.FileIOThread.c(SourceFile:51), net.minecraft.server.v1_8_R1.FileIOThread.run(SourceFile:30), java.lang.Thread.run(Unknown Source)], TIMED_WAITING Snooper Timer: [java.lang.Object.wait(Native Method), java.util.TimerThread.mainLoop(Unknown Source), java.util.TimerThread.run(Unknown Source)], RUNNABLE Server thread: [java.lang.Thread.dumpThreads(Native Method), java.lang.Thread.getAllStackTraces(Unknown Source), org.bukkit.craftbukkit.v1_8_R1.CraftCrashReport.call(CraftCrashReport.java:29), net.minecraft.server.v1_8_R1.CrashReportSystemDetails.a(SourceFile:78), net.minecraft.server.v1_8_R1.CrashReport.h(CrashReport.java:43), net.minecraft.server.v1_8_R1.CrashReport.<init>(CrashReport.java:32), net.minecraft.server.v1_8_R1.CrashReport.a(CrashReport.java:228), net.minecraft.server.v1_8_R1.World.tickEntities(World.java:1269), net.minecraft.server.v1_8_R1.WorldServer.tickEntities(WorldServer.java:539), net.minecraft.server.v1_8_R1.MinecraftServer.z(MinecraftServer.java:715), net.minecraft.server.v1_8_R1.DedicatedServer.z(DedicatedServer.java:284), net.minecraft.server.v1_8_R1.MinecraftServer.y(MinecraftServer.java:609), net.minecraft.server.v1_8_R1.MinecraftServer.run(MinecraftServer.java:517), java.lang.Thread.run(Unknown Source)],}
   Recent tasks from 1274-1304{ObsidianBreaker:com.creeperevents.oggehej.obsidianbreaker.ObsidianBreaker$CrackRunnable@1231,}
    Profiler Position: N/A (disabled)
    Player Count: 1 / 250; [EntityPlayer['johnny97mcc'/393, l='map_the_end', x=-2020.21, y=68.00, z=-67.39](johnny97mcc at -2020.2064115448507,68.0,-67.39153858689049)]
    Is Modded: Definitely; Server brand changed to 'CraftBukkit'
    Type: Dedicated Server (map_server.txt)

 

Does this occur when a certain player joins, or when any player joins?