Hopper: java.lang.ArrayIndexOutOfBoundsException: -7

java.lang.ArrayIndexOutOfBoundsException: -7
	at b.a(SourceFile:263)
	at b.a(SourceFile:250)
	at afn.h(SourceFile:1256)
	at mj.h(SourceFile:365)

---- Minecraft Crash Report ----
// Everything's going to plan. No, really, that was supposed to happen.

Time: 10/25/13 1:44 PM
Description: Exception ticking world entities

java.lang.ArrayIndexOutOfBoundsException: -7
	at b.a(SourceFile:263)
	at b.a(SourceFile:250)
	at afn.h(SourceFile:1256)
	at mj.h(SourceFile:365)
	at net.minecraft.server.MinecraftServer.u(SourceFile:511)
	at net.minecraft.server.MinecraftServer.t(SourceFile:441)
	at bsk.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:358)
	at ky.run(SourceFile:617)


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

-- Head --
Stacktrace:
	at b.a(SourceFile:263)
	at b.a(SourceFile:250)
	at afn.h(SourceFile:1256)
	at mj.h(SourceFile:365)

-- Affected level --
Details:
	Level name: hi
	All players: 1 total; [mm['commandoz530'/265, l='hi', x=-157.30, y=93.02, z=-59.08]]
	Chunk stats: ServerChunkCache: 982 Drop: 0
	Level seed: -4115981234458503409
	Level generator: ID 03 - amplified, ver 0. Features enabled: true
	Level generator options: 
	Level spawn location: World: (-128,64,244), Chunk: (at 0,4,4 in -8,15; contains blocks -128,0,240 to -113,255,255), Region: (-1,0; contains chunks -32,0 to -1,31, blocks -512,0,0 to -1,255,511)
	Level time: 18088 game time, 18088 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 58238 (now: false), thunder time: 91243 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.u(SourceFile:511)
	at net.minecraft.server.MinecraftServer.t(SourceFile:441)
	at bsk.t(SourceFile:117)
	at net.minecraft.server.MinecraftServer.run(SourceFile:358)
	at ky.run(SourceFile:617)

-- System Details --
Details:
	Minecraft Version: 1.7.2
	Operating System: Windows 8 (x86) version 6.2
	Java Version: 1.7.0_17, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 17848440 bytes (17 MB) / 518979584 bytes (494 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 6727 (376712 bytes; 0 MB) allocated, 3526 (197456 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 12, tallocated: 94
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 7885516 (441588896 bytes; 421 MB) allocated, 7885516 (441588896 bytes; 421 MB) used
	Player Count: 1 / 8; [mm['commandoz530'/265, l='hi', x=-157.30, y=93.02, z=-59.08]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.