client crashing server!!

A user logged in 3 times, each time he logged in it crashed the server

Code:

2012-01-09 20:17:20 [INFO] Disconnecting BAD-PLAYER [/x.x.x.x:61450]: Internal server error
2012-01-09 20:17:20 [WARNING] Failed to handle packet: java.lang.NullPointerException
java.lang.NullPointerException
    at net.minecraft.server.Packet21PickupSpawn.<init>(SourceFile:22)
    at net.minecraft.server.EntityTrackerEntry.b(EntityTrackerEntry.java:243)
    at net.minecraft.server.EntityTrackerEntry.b(EntityTrackerEntry.java:191)
    at net.minecraft.server.EntityTracker.track(EntityTracker.java:33)
    at net.minecraft.server.WorldManager.a(WorldManager.java:16)
    at net.minecraft.server.World.c(World.java:915)
    at net.minecraft.server.WorldServer.c(WorldServer.java:172)
    at net.minecraft.server.World.addEntity(World.java:908)
    at net.minecraft.server.World.addEntity(World.java:860)
    at net.minecraft.server.ServerConfigurationManager.c(ServerConfigurationManager.java:138)
    at net.minecraft.server.NetLoginHandler.b(NetLoginHandler.java:113)
    at net.minecraft.server.NetLoginHandler.a(NetLoginHandler.java:39)
    at net.minecraft.server.NetworkListenThread.a(SourceFile:94)
    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:527)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)
2012-01-09 20:17:20 [INFO] Fetching addPacket for removed entity: CraftItem
2012-01-09 20:17:20 [SEVERE] java.lang.NullPointerException
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.Packet21PickupSpawn.<init>(SourceFile:22)
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.EntityTrackerEntry.b(EntityTrackerEntry.java:243)
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.EntityTrackerEntry.b(EntityTrackerEntry.java:191)
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.EntityTrackerEntry.scanPlayers(EntityTrackerEntry.java:232)
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.EntityTrackerEntry.track(EntityTrackerEntry.java:59)
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.EntityTracker.updatePlayers(EntityTracker.java:130)
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:532)
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
2012-01-09 20:17:20 [SEVERE]     at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)
2012-01-09 20:17:20 [SEVERE] Unexpected exception
java.lang.NullPointerException
    at net.minecraft.server.Packet21PickupSpawn.<init>(SourceFile:22)
    at net.minecraft.server.EntityTrackerEntry.b(EntityTrackerEntry.java:243)
    at net.minecraft.server.EntityTrackerEntry.b(EntityTrackerEntry.java:191)
    at net.minecraft.server.EntityTrackerEntry.scanPlayers(EntityTrackerEntry.java:232)
    at net.minecraft.server.EntityTrackerEntry.track(EntityTrackerEntry.java:59)
    at net.minecraft.server.EntityTracker.updatePlayers(EntityTracker.java:130)
    at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:532)
    at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:425)
    at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)

Linux HOSTNAME 2.6.38-13-generic #53-Ubuntu SMP Mon Nov 28 19:33:45 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
java version "1.6.0_22"
OpenJDK Runtime Environment (IcedTea6 1.10.4) (6b22-1.10.4-0ubuntu1~11.04.1)
OpenJDK 64-Bit Server VM (build 20.0-b11, mixed mode)


Craftbukkit version git-Bukkit-1.0.1-R1-b1597jnks (MC: 1.0.1) (Implementing API version 1.0.1-R1)


Plugins: FoundDiamonds, Essentials, iQuest, MultiInv, Armageddon, PermissionsEx, VirtualShop, WaterproofRedstone, AngryWolves, MuddersMilk, AutoItemBarReload, Vault, HeroicDeath, Residence, iConomy, AutoPlant, HealMe, CraftBukkitUpToDate, nSpleef, WorldEdit, LightningGiants, ColoredSigns, ZeldaChickens, WorldGuard, Multiverse-Core, Lumberjack, ServerGoblins, Spout, Questioner, AfkKick, NoCheat, VirtualShopGUI, VoxelSniper, Modifyworld, LogBlockQuestioner, EssentialsSpawn, SoftLanding, MultipleHomes, EssentialsChat, PvPReward, EssentialsProtect, NSCommand, AppleTree, AutoMessage, Buycraft, Permissions, MCSL, BigCatch, mcMMO, LogBlock, WorldBorder, MonsterHunt, dynmap, SimpleClans, MobArena, VanishNoPacket, PreciousStones, MobBounty, BaseBukkitPlugin

 

Does this happen with all plugins disabled?

 

2012-01-09 21:31:39 [INFO] BAD-PLAYER [/x.x.x.x:59098] logged in with entity id 146767 at ([Survival] 1707.65625, 61.38625, -181.46875)
2012-01-09 21:31:39 [INFO] Fetching addPacket for removed entity: CraftItem
2012-01-09 21:31:39 [INFO] Disconnecting BAD [/x.x..x.x:59098]: Internal server error
2012-01-09 21:31:39 [WARNING] Failed to handle packet: java.lang.NullPointerException
java.lang.NullPointerException

I will test that - just had it happen again with a diff player

 

Is your server in offline mode?
Also, sent you a PM

 

online-mode=true