Hopper: java.lang.ArrayIndexOutOfBoundsException: -5

java.lang.ArrayIndexOutOfBoundsException: -5
	at b.a(SourceFile:330)
	at abw.a(SourceFile:2577)
	at net.minecraft.server.MinecraftServer.t(SourceFile:474)
	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)

---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!

Time: 9/19/13 9:21 PM
Description: Exception in server tick loop

java.lang.ArrayIndexOutOfBoundsException: -5
	at b.a(SourceFile:330)
	at abw.a(SourceFile:2577)
	at net.minecraft.server.MinecraftServer.t(SourceFile:474)
	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:
---------------------------------------------------------------------------------------

-- System Details --
Details:
	Minecraft Version: 1.6.4
	Operating System: Windows 7 (x86) version 6.1
	Java Version: 1.7.0_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 8322912 bytes (7 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: 893 (50008 bytes; 0 MB) allocated, 75 (4200 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 0, tallocated: 0
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 5823 (326088 bytes; 0 MB) allocated, 10 (560 bytes; 0 MB) used
	Player Count: 1 / 8; [jv['sockterrier'/202525, l='New Worldummy', x=-1387.50, y=16.00, z=817.50]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.