Bukkit

The system does not work and puts errors in buckle :

2013-03-24 02:49:10 [SEVERE] Could not pass event CreatureSpawnEvent to BackFromTheDead v0.9.1
org.bukkit.event.EventException
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
    at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
    at org.bukkit.craftbukkit.v1_4_R1.event.CraftEventFactory.callCreatureSpawnEvent(CraftEventFactory.java:227)
    at net.minecraft.server.v1_4_R1.World.addEntity(World.java:901)
    at net.minecraft.server.v1_4_R1.SpawnerCreature.spawnEntities(SpawnerCreature.java:159)
    at net.minecraft.server.v1_4_R1.WorldServer.doTick(WorldServer.java:157)
    at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:572)
    at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:224)
    at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
    at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
    at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.IllegalArgumentException: n must be positive
    at java.util.Random.nextInt(Random.java:300)
    at me.apollo.backfromthedead.backfromthedeadzombiecontrol.backfromthedeadzombiecontroller.getEntityToSpawn(backfromthedeadzombiecontroller.java:373)
    at me.apollo.backfromthedead.backfromthedeadzombiecontrol.backfromthedeadzombiecontroller.onZombieSpawn(backfromthedeadzombiecontroller.java:109)
    at sun.reflect.GeneratedMethodAccessor31.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
    ... 12 more

Make sure your giant zombie spawn chance is a positive number.

The problem is solved, I had put him has zero. There is well that zombies which appear from now on.