---- Minecraft Crash Report ----
// But it works on my machine.

Time: 7/30/14 9:51 PM
Description: Exception ticking world

java.lang.IllegalArgumentException: n must be positive
at java.util.Random.nextInt(Unknown Source)
at arl.a(SourceFile:224)
at arl.a(SourceFile:49)
at aqz.a(SourceFile:388)
at bfx.a(SourceFile:472)
at qn.a(SourceFile:174)
at bek.a(SourceFile:849)
at qn.c(SourceFile:104)
at qn.d(SourceFile:116)
at aqh.a(SourceFile:278)
at qo.h(SourceFile:327)
at qo.c(SourceFile:202)
at net.minecraft.server.MinecraftServer.y(SourceFile:598)
at net.minecraft.server.MinecraftServer.x(SourceFile:530)
at cxc.x(SourceFile:155)
at net.minecraft.server.MinecraftServer.run(SourceFile:446)
at java.lang.Thread.run(Unknown Source)

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 arl.a(SourceFile:224)
at arl.a(SourceFile:49)
at aqz.a(SourceFile:388)
at bfx.a(SourceFile:472)
at qn.a(SourceFile:174)
at bek.a(SourceFile:849)
at qn.c(SourceFile:104)
at qn.d(SourceFile:116)
at aqh.a(SourceFile:278)
at qo.h(SourceFile:327)
at qo.c(SourceFile:202)

– Affected level –
Details:
Level name: Rebuilt Snapshot World
All players: 1 total; [qr['Joebb3'/602, l='Rebuilt Snapshot World', x=-0.50, y=240.00, z=-13.50]]
Chunk stats: ServerChunkCache: 2579 Drop: 0
Level seed: -243863754
Level generator: ID 00 - default, ver 1. Features enabled: true
Level generator options:
Level spawn location: 196.00,64.00,256.00 - World: (196,64,256), Chunk: (at 4,4,0 in 12,16; contains blocks 192,0,256 to 207,255,271), Region: (0,0; contains chunks 0,0 to 31,31, blocks 0,0,0 to 511,255,511)
Level time: 428017 game time, 7834 day time
Level dimension: 0
Level storage version: 0x04ABD - Anvil
Level weather: Rain time: 1 (now: false), thunder time: 1 (now: false)
Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: true
Stacktrace:
at net.minecraft.server.MinecraftServer.y(SourceFile:598)
at net.minecraft.server.MinecraftServer.x(SourceFile:530)
at cxc.x(SourceFile:155)
at net.minecraft.server.MinecraftServer.run(SourceFile:446)
at java.lang.Thread.run(Unknown Source)

– System Details –
Details:
Minecraft Version: 14w31a
Operating System: Windows 7 (amd64) version 6.1
Java Version: 1.7.0_60, Oracle Corporation
Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Oracle Corporation
Memory: 420710888 bytes (401 MB) / 1157103616 bytes (1103 MB) up to 1908932608 bytes (1820 MB)
JVM Flags: 2 total; -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx2G
IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
Profiler Position: N/A (disabled)
Player Count: 1 / 8; [qr['Joebb3'/602, l='Rebuilt Snapshot World', x=-0.50, y=240.00, z=-13.50]]
Type: Integrated Server (map_client.txt)
Is Modded: Probably not. Jar signature remains and both client + server brands are untouched.