---- Minecraft Crash Report ----
// Why is it breaking :(

Time: 22-10-12 22:44
Description: Exception in server tick loop

java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
	at java.util.HashMap$KeyIterator.next(Unknown Source)
	at xq.a(SourceFile:72)
	at id.b(SourceFile:106)
	at net.minecraft.server.MinecraftServer.r(SourceFile:717)
	at net.minecraft.server.MinecraftServer.q(SourceFile:661)
	at bca.q(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:595)
	at fo.run(SourceFile:818)

Relevant Details:
- Minecraft Version: 1.4
- Operating System: Windows 7 (amd64) version 6.1
- Java Version: 1.7.0_07, Oracle Corporation
- Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
- Memory: 10533471560 bytes (10045 MB) / 12100894720 bytes (11540 MB) up to 12100894720 bytes (11540 MB)
- JVM Flags: 2 total; -Xmx12G -Xms12G
- Is Modded: Probably not
- Profiler Position: N/A (disabled)
- Vec3 Pool Size: 11706372 (655556832 bytes; 625 MB) allocated, 0 (0 bytes; 0 MB) used
- Player Count: 0 / 8; []
- World New World Entities: 0 total; []
- World New World Players: 0 total; []
- World New World Chunk Stats: ServerChunkCache: 0 Drop: 0
- Type: Integrated Server