Please help me with this error

[sledgemasterrrr]

[b#439]  2014-07-01 20:42:52 [sEVERE] [ForgeModLoader] Unable to launch

[b#439]  java.lang.reflect.InvocationTargetException

[b#439]   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

[b#439]   at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

[b#439]   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

[b#439]   at java.lang.reflect.Method.invoke(Unknown Source)

[b#439]   at net.minecraft.launchwrapper.Launch.launch(Launch.java:131)

[b#439]   at net.minecraft.launchwrapper.Launch.main(Launch.java:27)

[b#439]  Caused by: java.lang.NoClassDefFoundError: net/minecraft/block/Block

[b#439]   at net.minecraft.stats.StatList.func_75921_a(StatList.java:185)

[b#439]   at net.minecraft.stats.StatList.<clinit>(StatList.java:96)

[b#439]   at net.minecraft.client.Minecraft.<init>(Minecraft.java:329)

[b#439]   at net.minecraft.client.main.Main.main(SourceFile:83)

[b#439]   ... 6 more

[b#439]  Caused by: java.lang.ClassNotFoundException: net.minecraft.block.Block

[b#439]   at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:186)

[b#439]   at java.lang.ClassLoader.loadClass(Unknown Source)

[b#439]   at java.lang.ClassLoader.loadClass(Unknown Source)

[b#439]   ... 10 more

[b#439]  Caused by: java.lang.RuntimeException: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0

[b#439]   at codechicken.nei.asm.NEITransformer.transform(NEITransformer.java:155)

[b#439]   at net.minecraft.launchwrapper.LaunchClassLoader.runTransformers(LaunchClassLoader.java:274)

[b#439]   at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:172)

[b#439]   ... 12 more

[b#439]  Caused by: java.lang.IndexOutOfBoundsException: Index: 0, Size: 0

[b#439]   at java.util.LinkedList.checkElementIndex(Unknown Source)

[b#439]   at java.util.LinkedList.get(Unknown Source)

[b#439]   at codechicken.nei.asm.NEITransformer.transformer004(NEITransformer.java:120)

[b#439]   at codechicken.nei.asm.NEITransformer.transform(NEITransformer.java:149)

[b#439]   ... 14 more

   

 

 

Please help me with this error as i have no idea what it means. Thanks