Server crashed, now doesn't start.

My server is running Bukkit version 1.5.2-R0.2.

I was on my server and all of a sudden it crashed for some reason I don't know. Now that I try to start it again I get this error and it wont start.

Code:

2013-05-20 16:18:18 [SEVERE] Error occurred while enabling Multiverse-Core v2.4-b527 (Is it up to date?)
java.lang.OutOfMemoryError: Java heap space
    at net.minecraft.server.v1_5_R3.NBTTagByteArray.load(SourceFile:27)
    at net.minecraft.server.v1_5_R3.NBTBase.b(SourceFile:96)
    at net.minecraft.server.v1_5_R3.NBTTagCompound.load(SourceFile:34)
    at net.minecraft.server.v1_5_R3.NBTTagList.load(SourceFile:38)
    at net.minecraft.server.v1_5_R3.NBTBase.b(SourceFile:96)
    at net.minecraft.server.v1_5_R3.NBTTagCompound.load(SourceFile:34)
    at net.minecraft.server.v1_5_R3.NBTBase.b(SourceFile:96)
    at net.minecraft.server.v1_5_R3.NBTTagCompound.load(SourceFile:34)
    at net.minecraft.server.v1_5_R3.NBTBase.b(SourceFile:96)
    at net.minecraft.server.v1_5_R3.NBTCompressedStreamTools.a(SourceFile:75)
    at net.minecraft.server.v1_5_R3.ChunkRegionLoader.loadChunk(ChunkRegionLoader.java:80)
    at net.minecraft.server.v1_5_R3.ChunkRegionLoader.a(ChunkRegionLoader.java:45)
    at net.minecraft.server.v1_5_R3.ChunkProviderServer.loadChunk(ChunkProviderServer.java:176)
    at net.minecraft.server.v1_5_R3.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:105)
    at net.minecraft.server.v1_5_R3.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:84)
    at org.bukkit.craftbukkit.v1_5_R3.CraftServer.createWorld(CraftServer.java:759)
    at org.bukkit.Bukkit.createWorld(Bukkit.java:157)
    at org.bukkit.WorldCreator.createWorld(WorldCreator.java:235)
    at com.onarandombox.MultiverseCore.utils.WorldManager.addWorld(WorldManager.java:137)
    at com.onarandombox.MultiverseCore.utils.WorldManager.addWorld(WorldManager.java:91)
    at com.onarandombox.MultiverseCore.utils.WorldManager.loadWorlds(WorldManager.java:557)
    at com.onarandombox.MultiverseCore.MultiverseCore.onEnable(MultiverseCore.java:242)
    at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:217)
    at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:457)
    at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:381)
    at org.bukkit.craftbukkit.v1_5_R3.CraftServer.loadPlugin(CraftServer.java:282)
    at org.bukkit.craftbukkit.v1_5_R3.CraftServer.enablePlugins(CraftServer.java:264)
    at net.minecraft.server.v1_5_R3.MinecraftServer.j(MinecraftServer.java:304)
    at net.minecraft.server.v1_5_R3.MinecraftServer.e(MinecraftServer.java:283)
    at net.minecraft.server.v1_5_R3.MinecraftServer.a(MinecraftServer.java:243)
    at net.minecraft.server.v1_5_R3.DedicatedServer.init(DedicatedServer.java:151)
    at net.minecraft.server.v1_5_R3.MinecraftServer.run(MinecraftServer.java:382)
2013-05-20 16:18:18 [INFO] [AntiInvisibilityPotion] Enabling AntiInvisibilityPotion v1.35
2013-05-20 16:18:18 [INFO] AntiInvisibilityPotionversion1.35 is Enabled
2013-05-20 16:18:20 [INFO] [WorldGuard] Enabling WorldGuard v5.7.3
2013-05-20 16:18:54 [SEVERE] Exception in thread "Listen thread"
2013-05-20 16:18:59 [SEVERE] java.lang.OutOfMemoryError: Java heap space
2013-05-20 16:19:07 [SEVERE]    at java.util.jar.Manifest$FastInputStream.<init>(Unknown Source)
2013-05-20 16:20:15 [SEVERE] Error occurred (in the plugin loader) while enabling WorldGuard v5.7.3 (Is it up to date?)
java.lang.OutOfMemoryError: Java heap space
2013-05-20 16:20:24 [INFO] [Punishmental] Enabling Punishmental v4.1
2013-05-20 16:21:16 [SEVERE] Error occurred while enabling Punishmental v4.1 (Is it up to date?)
java.lang.OutOfMemoryError: Java heap space
2013-05-20 16:21:46 [SEVERE] Permission node 'punish.*' in plugin description file for Punishmental v4.1 is invalid
java.lang.OutOfMemoryError: Java heap space
2013-05-20 16:22:29 [SEVERE] Java heap space loading Punishmental v4.1 (Is it up to date?)
java.lang.OutOfMemoryError: Java heap space
2013-05-20 16:22:56 [INFO] [BetterEnderChest] Enabling BetterEnderChest v1.2.2
2013-05-20 16:24:21 [SEVERE] Error occurred while enabling BetterEnderChest v1.2.2 (Is it up to date?)
java.lang.OutOfMemoryError: Java heap space
2013-05-20 16:25:43 [INFO] Stopping server
2013-05-20 16:25:59 [INFO] [SafeCreeper] Disabling SafeCreeper v1.4.2

I think it's Multiverse Core some how but I just updated it to the newest version and it still doesn't work.

 

Out Of Memory

 

Your server is (obviously) running out of memory.

EDIT: Could be a JVM error if it's an onEnable error. If you're reloading the server, don't do that. Reloading is bad. If you're just starting it up, then it might be JVM-related.