at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:35)
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
at net.minecraft.server.v1_4_R1.EntityCreature.bn(EntityCreature.java:61)
at net.minecraft.server.v1_4_R1.EntityLiving.c(EntityLiving.java:1277)
at net.minecraft.server.v1_4_R1.EntityMonster.c(EntityMonster.java:20)
at net.minecraft.server.v1_4_R1.EntityLiving.j_(EntityLiving.java:534)
at net.minecraft.server.v1_4_R1.EntityMonster.j_(EntityMonster.java:24)
at net.minecraft.server.v1_4_R1.World.entityJoinedWorld(World.java:1332)
at net.minecraft.server.v1_4_R1.WorldServer.entityJoinedWorld(WorldServer.java:548)
at net.minecraft.server.v1_4_R1.World.playerJoinedWorld(World.java:1313)
at net.minecraft.server.v1_4_R1.World.tickEntities(World.java:1191)
at net.minecraft.server.v1_4_R1.WorldServer.tickEntities(WorldServer.java:445)
at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:580)
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.NullPointerException