Bukkit

What steps will reproduce the problem?
1. claim land, put up a sale sign
2. other user clicks sign to buy
3. takes mioney, and throws error in console

What is the expected output? What do you see instead?

What version of the product are you using?

lastest download of GP 8+, and latest download of GP-RE
spigot build 1649, with lastest patch applied

Do you have an error log of what happened?

[17:29:15 ERROR]: Could not pass event PlayerInteractEvent to GPRealEstate v1.4.1
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:509) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:494) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at org.bukkit.craftbukkit.v1_7_R4.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:242) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.PlayerInteractManager.interact(PlayerInteractManager.java:382) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.PlayerConnection.a(PlayerConnection.java:662) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.PacketPlayInBlockPlace.a(PacketPlayInBlockPlace.java:50) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.PacketPlayInBlockPlace.handle(PacketPlayInBlockPlace.java:86) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.NetworkManager.a(NetworkManager.java:186) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.ServerConnection.c(ServerConnection.java:81) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.MinecraftServer.v(MinecraftServer.java:734) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:289) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:584) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:490) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628) [spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
Caused by: java.lang.NoSuchMethodError: me.ryanhamshire.GriefPrevention.Claim.clearPermissions()Z
        at me.GuyB790.GPR.GPREListener.onSignInteract(GPREListener.java:374) ~[?:?]
        at sun.reflect.GeneratedMethodAccessor47.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_71]
        at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_71]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:298) ~[spigot.jar:git-Spigot-1.7.9-R0.2-207-g03373bb]
        ... 15 more

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