Hopper: java.lang.ArrayIndexOutOfBoundsException: -1

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-191037/

Crash:

java.lang.ArrayIndexOutOfBoundsException: -1
	at acv.a(SourceFile:81)
	at act.<init>(SourceFile:29)
	at acs.a(SourceFile:59)
	at acs.b(SourceFile:68)
	at acv.a(SourceFile:61)
	at adr.a(SourceFile:865)
	at abw.a(SourceFile:92)
	at abw.d(SourceFile:1925)
	at abw.y(SourceFile:1921)
	at js.g(SourceFile:257)
	at js.b(SourceFile:133)

The following is the first clean report made public about this crash:

---- Minecraft Crash Report ----
// On the bright side, I bought you a teddy bear!

Time: 20/9/2556, 17:59 น.
Description: Exception ticking world

java.lang.ArrayIndexOutOfBoundsException: -1
	at acv.a(SourceFile:81)
	at act.<init>(SourceFile:29)
	at acs.a(SourceFile:59)
	at acs.b(SourceFile:68)
	at acv.a(SourceFile:61)
	at adr.a(SourceFile:865)
	at abw.a(SourceFile:92)
	at abw.d(SourceFile:1925)
	at abw.y(SourceFile:1921)
	at js.g(SourceFile:257)
	at js.b(SourceFile:133)
	at net.minecraft.server.MinecraftServer.t(SourceFile:463)
	at net.minecraft.server.MinecraftServer.s(SourceFile:406)
	at bkz.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:340)
	at hi.run(SourceFile:583)


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

-- Head --
Stacktrace:
	at acv.a(SourceFile:81)
	at act.<init>(SourceFile:29)
	at acs.a(SourceFile:59)
	at acs.b(SourceFile:68)
	at acv.a(SourceFile:61)
	at adr.a(SourceFile:865)
	at abw.a(SourceFile:92)
	at abw.d(SourceFile:1925)
	at abw.y(SourceFile:1921)
	at js.g(SourceFile:257)
	at js.b(SourceFile:133)

-- Affected level --
Details:
	Level name: New World
	All players: 1 total; [jv['Funzaza'/58218, l='New World', x=-0.04, y=128.00, z=17.88]]
	Chunk stats: ServerChunkCache: 625 Drop: 0
	Level seed: 1781977625819922232
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (5,64,24), Chunk: (at 5,4,8 in 0,1; contains blocks 0,0,16 to 15,255,31), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
	Level time: 17455 game time, 17455 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 59920 (now: false), thunder time: 125679 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.t(SourceFile:463)
	at net.minecraft.server.MinecraftServer.s(SourceFile:406)
	at bkz.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:340)
	at hi.run(SourceFile:583)

-- System Details --
Details:
	Minecraft Version: 1.6.4
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_40, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 134471392 bytes (128 MB) / 318083072 bytes (303 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 3922 (219632 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 14, allocated: 3, tallocated: 63
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 595 (33320 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Player Count: 1 / 8; [jv['Funzaza'/58218, l='New World', x=-0.04, y=128.00, z=17.88]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.

You can see this full report at http://hopper.minecraft.net/crashes/minecraft/MCX-191037/12558312/