[07:51:41] [File IO Thread/WARN]: java.util.ConcurrentModificationException
[07:51:41] [File IO Thread/WARN]: 	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1437)
[07:51:41] [File IO Thread/WARN]: 	at java.util.HashMap$KeyIterator.next(HashMap.java:1461)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.nbt.NBTTagCompound.func_74734_a(NBTTagCompound.java:42)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.nbt.NBTTagList.func_74734_a(NBTTagList.java:32)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.nbt.NBTTagCompound.func_150298_a(NBTTagCompound.java:386)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.nbt.NBTTagCompound.func_74734_a(NBTTagCompound.java:44)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.nbt.NBTTagCompound.func_150298_a(NBTTagCompound.java:386)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.nbt.NBTTagCompound.func_74734_a(NBTTagCompound.java:44)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.nbt.CompressedStreamTools.func_150663_a(CompressedStreamTools.java:149)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.nbt.CompressedStreamTools.func_74800_a(CompressedStreamTools.java:139)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75821_a(AnvilChunkLoader.java:288)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.world.chunk.storage.AnvilChunkLoader.func_75814_c(AnvilChunkLoader.java:274)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.world.storage.ThreadedFileIOBase.func_75736_b(ThreadedFileIOBase.java:34)
[07:51:41] [File IO Thread/WARN]: 	at net.minecraft.world.storage.ThreadedFileIOBase.run(ThreadedFileIOBase.java:26)
[07:51:41] [File IO Thread/WARN]: 	at java.lang.Thread.run(Thread.java:745)