2011-06-29 10:10:26 [SEVERE] java.util.ConcurrentModificationException
2011-06-29 10:10:26 [SEVERE] 	at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
2011-06-29 10:10:26 [SEVERE] 	at java.util.AbstractList$Itr.next(AbstractList.java:343)
2011-06-29 10:10:26 [SEVERE] 	at java.util.AbstractCollection.removeAll(AbstractCollection.java:336)
2011-06-29 10:10:26 [SEVERE] 	at net.minecraft.server.Chunk.removeEntities(Chunk.java:476)
2011-06-29 10:10:26 [SEVERE] 	at net.minecraft.server.ChunkProviderServer.unloadChunks(ChunkProviderServer.java:250)
2011-06-29 10:10:26 [SEVERE] 	at net.minecraft.server.World.doTick(World.java:1627)
2011-06-29 10:10:26 [SEVERE] 	at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:441)
2011-06-29 10:10:26 [SEVERE] 	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:361)
2011-06-29 10:10:26 [SEVERE] 	at net.minecraft.server.ThreadServerApplication.run(SourceFile:422)
2011-06-29 10:10:26 [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(AbstractCollection.java:336)
	at net.minecraft.server.Chunk.removeEntities(Chunk.java:476)
	at net.minecraft.server.ChunkProviderServer.unloadChunks(ChunkProviderServer.java:250)
	at net.minecraft.server.World.doTick(World.java:1627)
	at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:441)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:361)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:422)