Server Fehler 1.6.6

Hallo Leute,
Unser Server geht sehr oft aus und Restartet...
Auf unserem Server kommt folgende Meldung

2011-06-03 16:09:18 [SEVERE] java.util.ConcurrentModificationException
2011-06-03 16:09:18 [SEVERE] at java.util.AbstractList$Itr.checkForComodification( AbstractList.java:372)
2011-06-03 16:09:18 [SEVERE] at java.util.AbstractList$Itr.next(AbstractList.java: 343)
2011-06-03 16:09:18 [SEVERE] at java.util.AbstractCollection.removeAll(AbstractCol lection.java:336)
2011-06-03 16:09:18 [SEVERE] at net.minecraft.server.Chunk.removeEntities(Chunk.ja va:476)
2011-06-03 16:09:18 [SEVERE] at net.minecraft.server.ChunkProviderServer.unloadChu nks(ChunkProviderServer.java:225)
2011-06-03 16:09:18 [SEVERE] at net.minecraft.server.World.doTick(World.java:1556)
2011-06-03 16:09:18 [SEVERE] at net.minecraft.server.MinecraftServer.h(MinecraftSe rver.java:391)
2011-06-03 16:09:18 [SEVERE] at net.minecraft.server.MinecraftServer.run(Minecraft Server.java:311)
2011-06-03 16:09:18 [SEVERE] at net.minecraft.server.ThreadServerApplication.run(S ourceFile:422)
2011-06-03 16:09:18 [SEVERE] Unexpected exception
java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification( AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java: 343)
at java.util.AbstractCollection.removeAll(AbstractCol lection.java:336)
at net.minecraft.server.Chunk.removeEntities(Chunk.ja va:476)
at net.minecraft.server.ChunkProviderServer.unloadChu nks(ChunkProviderServer.java:225)
at net.minecraft.server.World.doTick(World.java:1556)
at net.minecraft.server.MinecraftServer.h(MinecraftSe rver.java:391)
at net.minecraft.server.MinecraftServer.run(Minecraft Server.java:311)
at net.minecraft.server.ThreadServerApplication.run(S ourceFile:422)

Kann uns vllt. jemand sagen woran das liegen kann. ?

Unsere Plugins

"MyWarp" "dynmap" "IPGet" "FalseBookChat" "iConomyChestShop" "ScheduledAnnouncer" "BigBrother" "MyHome" "PlugMan" "MCDocs" "WorldGuard" "FalseBookExtra" "mcbans" "FalseBookCore" "FalseBookBlock" "Essentials" "AntiHack" "Elevators" "Permissions" "Minequery" "RemoteToolkitPlugin" "iConomy" "LWC" "CommandBook" "EssentialsChat" "MotherNature" "FalseBookIC" "ChestHarvester" "Jobs" "WorldEdit" "AuthMe" "FalseBookCart" "WormholeXTreme"

Ich hoffe auf schnelle Hilfe DANKE