2013-04-25 02:06:25 [SEVERE] "Silently" catching entity tracking error.
2013-04-25 02:06:25 [SEVERE] net.minecraft.server.v1_5_R2.ReportedException: Adding entity to track
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.EntityTracker.addEntity(EntityTracker.java:120)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.EntityTracker.addEntity(EntityTracker.java:88)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.EntityTracker.track(EntityTracker.java:23)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.WorldManager.a(WorldManager.java:18)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.World.a(World.java:1000)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.WorldServer.a(WorldServer.java:817)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.World.addEntity(World.java:993)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.World.addEntity(World.java:920)
2013-04-25 02:06:25 [SEVERE] 	at com.topcat.npclib.NPCManager$WL.onChunkLoad(NPCManager.java:95)
2013-04-25 02:06:25 [SEVERE] 	at sun.reflect.GeneratedMethodAccessor18.invoke(Unknown Source)
2013-04-25 02:06:25 [SEVERE] 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2013-04-25 02:06:25 [SEVERE] 	at java.lang.reflect.Method.invoke(Method.java:601)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:39)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:479)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:464)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:139)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:84)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.craftbukkit.v1_5_R2.CraftWorld.getChunkAt(CraftWorld.java:240)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.craftbukkit.v1_5_R2.CraftWorld.getBlockAt(CraftWorld.java:204)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.craftbukkit.v1_5_R2.CraftWorld.getBlockAt(CraftWorld.java:606)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.Location.getBlock(Location.java:82)
2013-04-25 02:06:25 [SEVERE] 	at com.topcat.npclib.NPCManager$WL.onChunkLoad(NPCManager.java:93)
2013-04-25 02:06:25 [SEVERE] 	at sun.reflect.GeneratedMethodAccessor18.invoke(Unknown Source)
2013-04-25 02:06:25 [SEVERE] 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2013-04-25 02:06:25 [SEVERE] 	at java.lang.reflect.Method.invoke(Method.java:601)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:39)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:479)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:464)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:139)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.ChunkProviderServer.getChunkAt(ChunkProviderServer.java:84)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.craftbukkit.v1_5_R2.CraftWorld.getChunkAt(CraftWorld.java:240)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.craftbukkit.v1_5_R2.CraftWorld.getBlockAt(CraftWorld.java:204)
2013-04-25 02:06:25 [SEVERE] 	at com.sk89q.worldguard.bukkit.WorldGuardBlockListener.onBlockFromTo(WorldGuardBlockListener.java:209)
2013-04-25 02:06:25 [SEVERE] 	at sun.reflect.GeneratedMethodAccessor94.invoke(Unknown Source)
2013-04-25 02:06:25 [SEVERE] 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
2013-04-25 02:06:25 [SEVERE] 	at java.lang.reflect.Method.invoke(Method.java:601)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:39)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:479)
2013-04-25 02:06:25 [SEVERE] 	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:464)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.BlockFlowing.a(BlockFlowing.java:144)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.WorldServer.a(WorldServer.java:564)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.WorldServer.doTick(WorldServer.java:206)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.MinecraftServer.r(MinecraftServer.java:553)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.DedicatedServer.r(DedicatedServer.java:223)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.MinecraftServer.q(MinecraftServer.java:471)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.MinecraftServer.run(MinecraftServer.java:403)
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.ThreadServerApplication.run(SourceFile:573)
2013-04-25 02:06:25 [SEVERE] Caused by: java.lang.IllegalStateException: Entity is already tracked!
2013-04-25 02:06:25 [SEVERE] 	at net.minecraft.server.v1_5_R2.EntityTracker.addEntity(EntityTracker.java:100)
2013-04-25 02:06:25 [SEVERE] 	... 52 more