---- Minecraft Crash Report ----
// Ooh. Shiny.

Time: 2/22/11 10:22 AM
Description: Exception ticking world

java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
	at java.util.HashMap$KeyIterator.next(Unknown Source)
	at zh.a(SourceFile:72)
	at iq.b(SourceFile:108)
	at net.minecraft.server.MinecraftServer.r(SourceFile:452)
	at net.minecraft.server.MinecraftServer.q(SourceFile:395)
	at bhc.q(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:329)
	at gi.run(SourceFile:565)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
	at java.util.HashMap$HashIterator.nextEntry(Unknown Source)
	at java.util.HashMap$KeyIterator.next(Unknown Source)
	at zh.a(SourceFile:72)
	at iq.b(SourceFile:108)

-- Affected level --
Details:
	Level name: challenge map
	All players: 1 total; [it['Player'/41845, l='challenge map', x=-289.77, y=76.00, z=262.31]]
	Chunk stats: ServerChunkCache: 709 Drop: 0
	Level seed: -6507932448233912746
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (-204,64,229), Chunk: (at 4,4,5 in -13,14; contains blocks -208,0,224 to -193,255,239), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 150119 game time, 6416 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 131345 (now: false), thunder time: 5035 (now: true)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.r(SourceFile:452)
	at net.minecraft.server.MinecraftServer.q(SourceFile:395)
	at bhc.q(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:329)
	at gi.run(SourceFile:565)

-- System Details --
Details:
	Minecraft Version: 13w03a
	Operating System: Windows Vista (x86) version 6.0
	Java Version: 1.6.0_07, Sun Microsystems Inc.
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode), Sun Microsystems Inc.
	Memory: 269103952 bytes (256 MB) / 676986880 bytes (645 MB) up to 1065484288 bytes (1016 MB)
	JVM Flags: 2 total; -Xms512m -Xmx1024m
	AABB Pool Size: 4145 (232120 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 1, tcache: 0, allocated: 1, tallocated: 63
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 1023 (57288 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Player Count: 1 / 8; [it['Player'/41845, l='challenge map', x=-289.77, y=76.00, z=262.31]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.