error1

[10:02:42] [Server thread/ERROR]: Could not pass event PlayerInteractEvent to GriefPrevention v8.2.3
org.bukkit.event.EventException
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigot.jar:git-Spigot-1627]
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-1627]
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot.jar:git-Spigot-1627]
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot.jar:git-Spigot-1627]
	at org.bukkit.craftbukkit.v1_7_R4.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:242) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.PlayerInteractManager.interact(PlayerInteractManager.java:375) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.PlayerConnection.a(PlayerConnection.java:662) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.PacketPlayInBlockPlace.a(SourceFile:60) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.PacketPlayInBlockPlace.handle(SourceFile:9) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.NetworkManager.a(NetworkManager.java:184) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.ServerConnection.c(ServerConnection.java:81) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.MinecraftServer.v(MinecraftServer.java:734) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:289) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:584) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:490) [spigot.jar:git-Spigot-1627]
	at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628) [spigot.jar:git-Spigot-1627]
Caused by: java.lang.IllegalArgumentException: Cannot measure distance between drcswek_nether and drcswek
	at org.bukkit.Location.distanceSquared(Location.java:448) ~[spigot.jar:git-Spigot-1627]
	at me.ryanhamshire.GriefPrevention.Visualization.Revert(Visualization.java:70) ~[?:?]
	at me.ryanhamshire.GriefPrevention.Visualization.Apply(Visualization.java:45) ~[?:?]
	at me.ryanhamshire.GriefPrevention.PlayerEventHandler.onPlayerInteract(PlayerEventHandler.java:1749) ~[?:?]
	at sun.reflect.GeneratedMethodAccessor40.invoke(Unknown Source) ~[?:?]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_51]
	at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_51]
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:298) ~[spigot.jar:git-Spigot-1627]
	... 15 more