java.lang.IllegalArgumentException: n must be positive
	at java.util.Random.nextInt(Unknown Source)
	at adv.a(SourceFile:121)
	at adv.a(SourceFile:26)
	at adp.a(SourceFile:349)
	at agc.a(SourceFile:429)
	at kc.a(SourceFile:156)
	at aez.a(SourceFile:765)
	at kc.c(SourceFile:93)
	at kc.d(SourceFile:104)
	at act.e(SourceFile:311)
	at kd.g(SourceFile:231)
	at kd.b(SourceFile:134)

---- Minecraft Crash Report ----
// Shall we play a game?

Time: 06/09/13 15.52
Description: Exception ticking world

java.lang.IllegalArgumentException: n must be positive
	at java.util.Random.nextInt(Unknown Source)
	at adv.a(SourceFile:121)
	at adv.a(SourceFile:26)
	at adp.a(SourceFile:349)
	at agc.a(SourceFile:429)
	at kc.a(SourceFile:156)
	at aez.a(SourceFile:765)
	at kc.c(SourceFile:93)
	at kc.d(SourceFile:104)
	at act.e(SourceFile:311)
	at kd.g(SourceFile:231)
	at kd.b(SourceFile:134)
	at net.minecraft.server.MinecraftServer.t(SourceFile:455)
	at net.minecraft.server.MinecraftServer.s(SourceFile:398)
	at bnn.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:332)
	at hr.run(SourceFile:575)


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

-- Head --
Stacktrace:
	at java.util.Random.nextInt(Unknown Source)
	at adv.a(SourceFile:121)
	at adv.a(SourceFile:26)
	at adp.a(SourceFile:349)
	at agc.a(SourceFile:429)
	at kc.a(SourceFile:156)
	at aez.a(SourceFile:765)
	at kc.c(SourceFile:93)
	at kc.d(SourceFile:104)
	at act.e(SourceFile:311)
	at kd.g(SourceFile:231)
	at kd.b(SourceFile:134)

-- Affected level --
Details:
	Level name: st4
	All players: 1 total; [kg['o0OAxialO0o'/752886, l='st4', x=-29999999,50, y=70,50, z=0,50]]
	Chunk stats: ServerChunkCache: 919 Drop: 0
	Level seed: 5679245943133425142
	Level generator: ID 00 - default, ver 1. Features enabled: true
	Level generator options: 
	Level spawn location: World: (-119,64,-157), Chunk: (at 9,4,3 in -8,-10; contains blocks -128,0,-160 to -113,255,-145), Region: (-1,-1; contains chunks -32,-32 to -1,-1, blocks -512,0,-512 to -1,255,-1)
	Level time: 2101 game time, 2101 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 29695 (now: false), thunder time: 122139 (now: false)
	Level game mode: Game mode: creative (ID 1). Hardcore: false. Cheats: true
Stacktrace:
	at net.minecraft.server.MinecraftServer.t(SourceFile:455)
	at net.minecraft.server.MinecraftServer.s(SourceFile:398)
	at bnn.s(SourceFile:124)
	at net.minecraft.server.MinecraftServer.run(SourceFile:332)
	at hr.run(SourceFile:575)

-- System Details --
Details:
	Minecraft Version: 13w36b
	Operating System: Windows 7 (amd64) version 6.1
	Java Version: 1.7.0_21, Oracle Corporation
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
	Memory: 3777734504 bytes (3602 MB) / 5168168960 bytes (4928 MB) up to 5168168960 bytes (4928 MB)
	JVM Flags: 3 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx5G -Xms5G
	AABB Pool Size: 7523 (421288 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 18316 (1025696 bytes; 0 MB) allocated, 0 (0 bytes; 0 MB) used
	Player Count: 1 / 8; [kg['o0OAxialO0o'/752886, l='st4', x=-29999999,50, y=70,50, z=0,50]]
	Type: Integrated Server (map_client.txt)
	Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.