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-87109/

Crash:

java.lang.IllegalArgumentException: n must be positive
	at java.util.Random.nextInt(Random.java:250)
	at adv.a(SourceFile:121)
	at adv.a(SourceFile:26)
	at adp.a(SourceFile:349)
	at aea.a(SourceFile:141)
	at agc.a(SourceFile:429)
	at kc.a(SourceFile:156)
	at aez.a(SourceFile:774)
	at kc.c(SourceFile:93)
	at kb.<init>(SourceFile:28)
	at ka.a(SourceFile:209)
	at ka.a(SourceFile:246)
	at hw.a(SourceFile:151)
	at hw.c(SourceFile:202)
	at hw.a(SourceFile:95)
	at bnq.b(SourceFile:73)
	at net.minecraft.server.MinecraftServer.t(SourceFile:481)
	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)

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

---- Minecraft Crash Report ----
// Don't be sad. I'll do better next time, I promise!

Time: 9/6/13 5:43 PM
Description: Exception in server tick loop

java.lang.IllegalArgumentException: n must be positive
	at java.util.Random.nextInt(Random.java:250)
	at adv.a(SourceFile:121)
	at adv.a(SourceFile:26)
	at adp.a(SourceFile:349)
	at aea.a(SourceFile:141)
	at agc.a(SourceFile:429)
	at kc.a(SourceFile:156)
	at aez.a(SourceFile:774)
	at kc.c(SourceFile:93)
	at kb.<init>(SourceFile:28)
	at ka.a(SourceFile:209)
	at ka.a(SourceFile:246)
	at hw.a(SourceFile:151)
	at hw.c(SourceFile:202)
	at hw.a(SourceFile:95)
	at bnq.b(SourceFile:73)
	at net.minecraft.server.MinecraftServer.t(SourceFile:481)
	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:
---------------------------------------------------------------------------------------

-- System Details --
Details:
	Minecraft Version: 13w36b
	Operating System: Mac OS X (x86_64) version 10.8.4
	Java Version: 1.6.0_51, Apple Inc.
	Java VM Version: Java HotSpot(TM) 64-Bit Server VM (mixed mode), Apple Inc.
	Memory: 50914424 bytes (48 MB) / 171814912 bytes (163 MB) up to 1065025536 bytes (1015 MB)
	JVM Flags: 1 total; -Xmx1G
	AABB Pool Size: 1362 (76272 bytes; 0 MB) allocated, 1289 (72184 bytes; 0 MB) used
	IntCache: cache: 0, tcache: 0, allocated: 13, tallocated: 95
	Profiler Position: N/A (disabled)
	Vec3 Pool Size: 183 (10248 bytes; 0 MB) allocated, 183 (10248 bytes; 0 MB) used
	Player Count: 1 / 8; [kg['Reality_Field'/81, l='New World', x=29999999.50, y=80.50, z=0.50]]
	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-87109/8508560/