error

23:09:15 [SEVERE] Could not pass event McMMOPlayerLevelUpEvent to ItemRules v1.0.8
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.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
        at com.gmail.nossr50.skills.utilities.SkillTools.xpCheckSkill(SkillTools.java:244)
        at com.gmail.nossr50.datatypes.McMMOPlayer.applyXpGain(McMMOPlayer.java:113)
        at com.gmail.nossr50.commands.admin.AddxpCommand.onCommand(AddxpCommand.java:132)
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:186)
        at org.bukkit.craftbukkit.v1_4_R1.CraftServer.dispatchCommand(CraftServer.java:514)
        at net.minecraft.server.v1_4_R1.PlayerConnection.handleCommand(PlayerConnection.java:980)
        at net.minecraft.server.v1_4_R1.PlayerConnection.chat(PlayerConnection.java:898)
        at net.minecraft.server.v1_4_R1.PlayerConnection.a(PlayerConnection.java:853)
        at net.minecraft.server.v1_4_R1.Packet3Chat.handle(Packet3Chat.java:44)
        at net.minecraft.server.v1_4_R1.NetworkManager.b(NetworkManager.java:290)
        at net.minecraft.server.v1_4_R1.PlayerConnection.d(PlayerConnection.java:113)
        at net.minecraft.server.v1_4_R1.ServerConnection.b(SourceFile:39)
        at net.minecraft.server.v1_4_R1.DedicatedServerConnection.b(SourceFile:30)
        at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:598)
        at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:224)
        at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
        at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
        at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NullPointerException
        at com.github.mineGeek.ItemRules.Integration.McMMOEventListener.onMcMMOExperience(McMMOEventListener.java:32)
        at sun.reflect.GeneratedMethodAccessor188.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)
        ... 22 more