Hopper: java.lang.IllegalArgumentException: n must be positive

This is an automatically generated report based from the following crash: http://hopper.minecraft.net/crashes/minecraft/MCX-223722/

Crash:

java.lang.IllegalArgumentException: n must be positive
	at java.util.Random.nextInt(Unknown Source)
	at aaw.a(SourceFile:144)
	at of.c(SourceFile:800)
	at of.d(SourceFile:816)
	at of.a(SourceFile:570)
	at tm.a(SourceFile:43)
	at tw.a(SourceFile:146)
	at of.b(SourceFile:741)
	at nn.a(SourceFile:701)
	at of.a(SourceFile:153)
	at nn.d(SourceFile:577)
	at of.e(SourceFile:1096)
	at of.c(SourceFile:1321)
	at og.c(SourceFile:292)
	at tm.c(SourceFile:24)
	at tw.c(SourceFile:141)
	at of.l_(SourceFile:1176)
	at og.l_(SourceFile:169)
	at tm.l_(SourceFile:29)
	at tw.l_(SourceFile:197)
	at abw.a(SourceFile:1349)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)

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

---- Minecraft Crash Report ----
// I bet Cylons wouldn't have this problem.

Time: 13/09/23 17:10
Description: Ticking entity

java.lang.IllegalArgumentException: n must be positive
	at java.util.Random.nextInt(Unknown Source)
	at aaw.a(SourceFile:144)
	at of.c(SourceFile:800)
	at of.d(SourceFile:816)
	at of.a(SourceFile:570)
	at tm.a(SourceFile:43)
	at tw.a(SourceFile:146)
	at of.b(SourceFile:741)
	at nn.a(SourceFile:701)
	at of.a(SourceFile:153)
	at nn.d(SourceFile:577)
	at of.e(SourceFile:1096)
	at of.c(SourceFile:1321)
	at og.c(SourceFile:292)
	at tm.c(SourceFile:24)
	at tw.c(SourceFile:141)
	at of.l_(SourceFile:1176)
	at og.l_(SourceFile:169)
	at tm.l_(SourceFile:29)
	at tw.l_(SourceFile:197)
	at abw.a(SourceFile:1349)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)
	at abw.h(SourceFile:1234)
	at js.h(SourceFile:364)
	at net.minecraft.server.MinecraftServer.t(SourceFile:471)
	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 java.util.Random.nextInt(Unknown Source)
	at aaw.a(SourceFile:144)
	at of.c(SourceFile:800)
	at of.d(SourceFile:816)
	at of.a(SourceFile:570)
	at tm.a(SourceFile:43)
	at tw.a(SourceFile:146)
	at of.b(SourceFile:741)
	at nn.a(SourceFile:701)
	at of.a(SourceFile:153)
	at nn.d(SourceFile:577)
	at of.e(SourceFile:1096)
	at of.c(SourceFile:1321)
	at og.c(SourceFile:292)
	at tm.c(SourceFile:24)
	at tw.c(SourceFile:141)
	at of.l_(SourceFile:1176)
	at og.l_(SourceFile:169)
	at tm.l_(SourceFile:29)
	at tw.l_(SourceFile:197)
	at abw.a(SourceFile:1349)
	at js.a(SourceFile:479)
	at abw.g(SourceFile:1327)

-- Entity being ticked --
Details:
	Entity Type: Zombie (tw)
	Entity ID: 1112725
	Entity Name: 深淵様
	Entity's Exact location: 36.36, 3.00, -3.14
	Entity's Block location: World: (36,3,-4), Chunk: (at 4,0,12 in 2,-1; contains blocks 32,0,-16 to 47,255,-1), Region: (0,-1; contains chunks 0,-32 to 31,-1, blocks 0,0,-512 to 511,255,-1)
	Entity's Momentum: 0.12, -2.06, 0.11
Stacktrace:
	at abw.h(SourceFile:1234)
	at js.h(SourceFile:364)

-- Affected level --
Details:
	Level name: The Unusual SkyBlock
	All players: 1 total; [jv['Folora'/264123, l='The Unusual SkyBlock', x=40.34, y=5.00, z=-19.58]]
	Chunk stats: ServerChunkCache: 1165 Drop: 0
	Level seed: 1435672245
	Level generator: ID 01 - flat, ver 0. Features enabled: false
	Level generator options: 2;0;12;biome_1,village
	Level spawn location: World: (-1911,114,-137), Chunk: (at 9,7,7 in -120,-9; contains blocks -1920,0,-144 to -1905,255,-129), Region: (-4,-1; contains chunks -128,-32 to -97,-1, blocks -2048,0,-512 to -1537,255,-1)
	Level time: 1032058 game time, 20366 day time
	Level dimension: 0
	Level storage version: 0x04ABD - Anvil
	Level weather: Rain time: 42520 (now: false), thunder time: 40470 (now: false)
	Level game mode: Game mode: survival (ID 0). Hardcore: false. Cheats: false
Stacktrace:
	at net.minecraft.server.MinecraftServer.t(SourceFile:471)
	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_25, Oracle Corporation
	Java VM Version: Java HotSpot(TM) Client VM (mixed mode, sharing), Oracle Corporation
	Memory: 141263216 bytes (134 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: 2805 (157080 bytes; 0 MB) allocated, 2517 (140952 bytes; 0 MB) used
	Suspicious classes: No suspicious classes found.
	IntCache: cache: 0, tcache: 0, allocated: 3, tallocated: 63
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 591 (33096 bytes; 0 MB) allocated, 301 (16856 bytes; 0 MB) used
	Player Count: 1 / 8; [jv['Folora'/264123, l='The Unusual SkyBlock', x=40.34, y=5.00, z=-19.58]]
	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-223722/13640235/