Hopper: java.lang.ArrayIndexOutOfBoundsException: 623

java.lang.ArrayIndexOutOfBoundsException: 623
	at aef.a(SourceFile:123)

---- Minecraft Crash Report ----
// Sorry :(

Time: 9/12/13 4:52 PM
Description: Invalid Biome id

java.lang.ArrayIndexOutOfBoundsException: 151720
	at aef.a(SourceFile:123)
	at agl.a(SourceFile:90)
	at agl.d(SourceFile:189)
	at kk.c(SourceFile:72)
	at kj.<init>(SourceFile:28)
	at ki.a(SourceFile:209)
	at ki.a(SourceFile:246)
	at jf.a(SourceFile:151)
	at jf.c(SourceFile:202)
	at jf.a(SourceFile:95)
	at bnz.b(SourceFile:73)
	at net.minecraft.server.MinecraftServer.u(SourceFile:482)
	at net.minecraft.server.MinecraftServer.t(SourceFile:399)
	at bnw.t(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:333)
	at ja.run(SourceFile:576)


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

-- Head --
Stacktrace:
	at aef.a(SourceFile:123)

-- RawBiomeBlock --
Details:
	biomes[] size: 256
	x: -74
	z: 86
	w: 10
	h: 10
Stacktrace:
	at aef.a(SourceFile:123)
	at agl.a(SourceFile:90)
	at agl.d(SourceFile:189)

-- Chunk to be generated --
Details:
	Location: -18,22
	Position hash: 98784247790
	Generator: RandomLevelSource
Stacktrace:
	at kk.c(SourceFile:72)
	at kj.<init>(SourceFile:28)
	at ki.a(SourceFile:209)
	at ki.a(SourceFile:246)
	at jf.a(SourceFile:151)
	at jf.c(SourceFile:202)
	at jf.a(SourceFile:95)
	at bnz.b(SourceFile:73)
	at net.minecraft.server.MinecraftServer.u(SourceFile:482)
	at net.minecraft.server.MinecraftServer.t(SourceFile:399)
	at bnw.t(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:333)
	at ja.run(SourceFile:576)

-- System Details --
Details:
	Minecraft Version: 13w37a
	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: 114214552 bytes (108 MB) / 197742592 bytes (188 MB) up to 518979584 bytes (494 MB)
	JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M
	AABB Pool Size: 2309 (129304 bytes; 0 MB) allocated, 2309 (129304 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 125
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 278 (15568 bytes; 0 MB) allocated, 278 (15568 bytes; 0 MB) used
	Player Count: 1 / 8; [ko['GTFO_NOW'/184, l='1.7 Snapshot', x=-116.37, y=88.57, z=407.09]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.