[SEVERE] Could not pass event PlayerInteractEvent to SignMaster
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:304)
        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.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:177)
        at org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:147)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:890)
        at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:151)
        at net.minecraft.server.Packet18ArmAnimation.handle(SourceFile:38)
        at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:114)
        at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:83)
        at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:83)
        at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:569)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:461)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
        at Orcem.Modding.SignMaster.Listener.PlayerListener.onPlayerInteract(PlayerListener.java:40)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.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:302)
        ... 15 more