Description: Exception in server tick loop

cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: Lnet/minecraft/item/EnumRarity;
	at cpw.mods.fml.common.LoadController.transition(LoadController.java:147)
	at cpw.mods.fml.common.Loader.initializeMods(Loader.java:697)
	at cpw.mods.fml.server.FMLServerHandler.finishServerLoading(FMLServerHandler.java:93)
	at cpw.mods.fml.common.FMLCommonHandler.onServerStarted(FMLCommonHandler.java:355)
	at net.minecraft.server.dedicated.DedicatedServer.func_71197_b(DedicatedServer.java:168)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:574)
	at net.minecraft.server.ThreadMinecraftServer.run(SourceFile:573)
Caused by: java.lang.NoClassDefFoundError: Lnet/minecraft/item/EnumRarity;
	at java.lang.Class.getDeclaredFields0(Native Method)
	at java.lang.Class.privateGetDeclaredFields(Unknown Source)
	at java.lang.Class.getField0(Unknown Source)
	at java.lang.Class.getField(Unknown Source)
	at com.minalien.dartpatch.DartPatch.getDartItem(DartPatch.java:51)
	at com.minalien.dartpatch.DartPatch.modsLoaded(DartPatch.java:82)
	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 cpw.mods.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:494)
	at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
	at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
	at com.google.common.eventbus.EventBus.post(EventBus.java:267)
	at cpw.mods.fml.common.LoadController.sendEventToModContainer(LoadController.java:192)
	at cpw.mods.fml.common.LoadController.propogateStateMessage(LoadController.java:172)
	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 com.google.common.eventbus.EventHandler.handleEvent(EventHandler.java:74)
	at com.google.common.eventbus.SynchronizedEventHandler.handleEvent(SynchronizedEventHandler.java:45)
	at com.google.common.eventbus.EventBus.dispatch(EventBus.java:314)
	at com.google.common.eventbus.EventBus.dispatchQueuedEvents(EventBus.java:296)
	at com.google.common.eventbus.EventBus.post(EventBus.java:267)
	at cpw.mods.fml.common.LoadController.distributeStateMessage(LoadController.java:103)
	at cpw.mods.fml.common.Loader.initializeMods(Loader.java:696)
	... 5 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.item.EnumRarity
	at cpw.mods.fml.relauncher.RelaunchClassLoader.findClass(RelaunchClassLoader.java:273)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 37 more
Caused by: java.lang.NullPointerException