Bukkit

2013-01-12 18:04:05 [SEVERE] Could not pass event PlayerInteractEntityEvent to ResProtect v0.7
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.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_6.PlayerConnection.a(PlayerConnection.java:1107)
    at net.minecraft.server.v1_4_6.Packet7UseEntity.handle(SourceFile:36)
    at net.minecraft.server.v1_4_6.NetworkManager.b(NetworkManager.java:290)
    at net.minecraft.server.v1_4_6.PlayerConnection.d(PlayerConnection.java:112)
    at net.minecraft.server.v1_4_6.ServerConnection.b(SourceFile:39)
    at net.minecraft.server.v1_4_6.DedicatedServerConnection.b(SourceFile:30)
    at net.minecraft.server.v1_4_6.MinecraftServer.r(MinecraftServer.java:585)
    at net.minecraft.server.v1_4_6.DedicatedServer.r(DedicatedServer.java:224)
    at net.minecraft.server.v1_4_6.MinecraftServer.q(MinecraftServer.java:481)
    at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:416)
    at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NullPointerException
    at com.almuramc.resprotect.EntityTradeListener.onPlayerInteractEntity(EntityTradeListener.java:56)
    at sun.reflect.GeneratedMethodAccessor160.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
    ... 15 more