[SEVERE] Could not pass event ChunkLoadEvent to NaturalHorses v1.0.7
org.bukkit.event.EventException
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
	at org.bukkit.craftbukkit.v1_6_R2.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:58)
	at org.bukkit.craftbukkit.v1_6_R2.chunkio.ChunkIOProvider.callStage2(ChunkIOProvider.java:13)
	at org.bukkit.craftbukkit.v1_6_R2.util.AsynchronousExecutor$Task.finish(AsynchronousExecutor.java:179)
	at org.bukkit.craftbukkit.v1_6_R2.util.AsynchronousExecutor.finishActive(AsynchronousExecutor.java:287)
	at org.bukkit.craftbukkit.v1_6_R2.chunkio.ChunkIOExecutor.tick(ChunkIOExecutor.java:30)
	at net.minecraft.server.v1_6_R2.MinecraftServer.t(MinecraftServer.java:529)
	at net.minecraft.server.v1_6_R2.DedicatedServer.t(DedicatedServer.java:226)
	at net.minecraft.server.v1_6_R2.MinecraftServer.s(MinecraftServer.java:486)
	at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java:419)
	at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:582)
Caused by: java.lang.IllegalArgumentException: Cannot spawn an entity for org.bukkit.entity.Horse
	at org.bukkit.craftbukkit.v1_6_R2.CraftWorld.spawn(CraftWorld.java:1022)
	at org.bukkit.craftbukkit.v1_6_R2.CraftWorld.spawn(CraftWorld.java:792)
	at org.bukkit.craftbukkit.v1_6_R2.CraftWorld.spawnEntity(CraftWorld.java:339)
	at au.com.addstar.naturalhorses.ChunkListener.onChunkLoad(ChunkListener.java:96)
	at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
	... 13 more