11:21:52 [SEVERE] Could not pass event PlayerGameModeChangeEvent to RestrictCreative v1.5.6
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:26)
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:479)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:464)
        at org.bukkit.craftbukkit.v1_5_R2.entity.CraftPlayer.setGameMode(CraftPlayer.java:551)
        at com.onarandombox.MultiverseCore.listeners.MVPlayerListener$2.run(MVPlayerListener.java:349)
        at org.bukkit.craftbukkit.v1_5_R2.scheduler.CraftTask.run(CraftTask.java:58)
        at org.bukkit.craftbukkit.v1_5_R2.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:344)
        at net.minecraft.server.v1_5_R2.MinecraftServer.r(MinecraftServer.java:506)
        at net.minecraft.server.v1_5_R2.DedicatedServer.r(DedicatedServer.java:229)
        at net.minecraft.server.v1_5_R2.MinecraftServer.q(MinecraftServer.java:469)
        at net.minecraft.server.v1_5_R2.MinecraftServer.run(MinecraftServer.java:401)
        at net.minecraft.server.v1_5_R2.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.NoClassDefFoundError: org/bukkit/craftbukkit/v1_5_R1/inventory/CraftItemStack
        at net.endercraftbuild.inventories.InvManager.saveInventory(InvManager.java:46)
        at net.endercraftbuild.inventories.InvManager.onPlayerGameModeChange(InvManager.java:32)
        at sun.reflect.GeneratedMethodAccessor482.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:425)
        ... 13 more
Caused by: java.lang.ClassNotFoundException: org.bukkit.craftbukkit.v1_5_R1.inventory.CraftItemStack
        at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:70)
        at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        ... 19 more