---- Minecraft Crash Report ----
// Don't be sad. I'll do better next time, I promise!

Time: 2013-03-02 15:12
Description: Adding entity to track

java.lang.IllegalStateException: Entity is already tracked!
	at it.a(SourceFile:76)
	at it.a(SourceFile:61)
	at iv.a(SourceFile:24)
	at zv.a(SourceFile:866)
	at iz.a(SourceFile:632)
	at zv.d(SourceFile:858)
	at amn.k(SourceFile:55)
	at amn.a(SourceFile:35)
	at iz.a(SourceFile:430)
	at iz.b(SourceFile:142)
	at net.minecraft.server.MinecraftServer.r(SourceFile:454)
	at net.minecraft.server.MinecraftServer.q(SourceFile:397)
	at bja.q(SourceFile:122)
	at net.minecraft.server.MinecraftServer.run(SourceFile:331)
	at gp.run(SourceFile:573)


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

-- Entity To Track --
Details:
	Tracking range: 144 blocks
	Update interval: Once per 20 ticks
	Entity Type: FallingSand (ra)
	Entity ID: 10238
	Entity Name: Falling Block
	Entity's Exact location: 161,50, 43,50, 179,50
	Entity's Block location: World: (161,43,179), Chunk: (at 1,2,3 in 10,11; contains blocks 160,0,176 to 175,255,191), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Entity's Momentum: 0,00, 0,00, 0,00
	Immitating block ID: 13
	Immitating block data: 0
Stacktrace:
	at it.a(SourceFile:76)
	at it.a(SourceFile:61)
	at iv.a(SourceFile:24)
	at zv.a(SourceFile:866)
	at iz.a(SourceFile:632)
	at zv.d(SourceFile:858)
	at amn.k(SourceFile:55)
	at amn.a(SourceFile:35)

-- Block being ticked --
Details:
	Block type: ID #13 (tile.gravel // amk)
	Block data value: 0 / 0x0 / 0b0000
	Block location: World: (161,43,179), Chunk: (at 1,2,3 in 10,11; contains blocks 160,0,176 to 175,255,191), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Stacktrace:
	at iz.a(SourceFile:430)
	at iz.b(SourceFile:142)

-- Affected level --
Details:
	Level name: jærnvæg
	All players: 1 total; [jc['h4xxel'/220, l='jærnvæg', x=220,93, y=120,53, z=258,81]]
	Chunk stats: ServerChunkCache: 625 Drop: 0
	Level seed: 1844876007
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (220,64,256), Chunk: (at 12,4,0 in 13,16; contains blocks 208,0,256 to 223,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 290 game time, 290 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 123522 (now: false), thunder time: 164575 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.r(SourceFile:454)
	at net.minecraft.server.MinecraftServer.q(SourceFile:397)
	at bja.q(SourceFile:122)
	at net.minecraft.server.MinecraftServer.run(SourceFile:331)
	at gp.run(SourceFile:573)

-- System Details --
Details:
	Minecraft Version: 13w09c
	Operating System: Linux (amd64) version 3.5.0-25-generic
	Java Version: 1.7.0_15, Oracle Corporation
	Java VM Version: OpenJDK 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 205328792 bytes (195 MB) / 433848320 bytes (413 MB) up to 954466304 bytes (910 MB)
	JVM Flags: 2 total; -Xmx1024M -Xms512M
	AABB Pool Size: 13740 (769440 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 1174 (65744 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Player Count: 1 / 8; [jc['h4xxel'/220, l='jærnvæg', x=220,93, y=120,53, z=258,81]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.