CleanRoomGenerator Error

Description: Exception in server tick loop

java.lang.IllegalArgumentException: n must be positive
	at java.util.Random.nextInt(Unknown Source)
	at net.minecraft.server.v1_7_R1.BiomeDecorator.a(SourceFile:122)
	at net.minecraft.server.v1_7_R1.BiomeDecorator.a(SourceFile:27)
	at net.minecraft.server.v1_7_R1.BiomeBase.a(SourceFile:362)
	at net.minecraft.server.v1_7_R1.ChunkProviderGenerate.getChunkAt(SourceFile:432)
	at org.bukkit.craftbukkit.v1_7_R1.generator.NormalChunkGenerator.getChunkAt(NormalChunkGenerator.java:49)
	at net.minecraft.server.v1_7_R1.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:226)
	at net.minecraft.server.v1_7_R1.Chunk.a(Chunk.java:817)
	at org.bukkit.craftbukkit.v1_7_R1.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:61)
	at org.bukkit.craftbukkit.v1_7_R1.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:13)
	at org.bukkit.craftbukkit.v1_7_R1.util.AsynchronousExecutor$Task.finish(AsynchronousExecutor.java:179)
	at org.bukkit.craftbukkit.v1_7_R1.util.AsynchronousExecutor.finishActive(AsynchronousExecutor.java:287)
	at org.bukkit.craftbukkit.v1_7_R1.chunkio.ChunkIOExecutor.tick(ChunkIOExecutor.java:30)
	at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:594)
	at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:250)
	at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:545)
	at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:457)
	at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617)