DataNucleus Enhancer Error

[user3370788 via StackOverflow]

I get the below error when I generate google backend, I am a frustrated newbie, please help me :)

java.lang.RuntimeException: Unexpected exception at com.google.appengine.tools.enhancer.Enhancer.execute(Enhancer.java:76) at com.google.appengine.tools.enhancer.Enhance.(Enhance.java:71) at com.google.appengine.tools.enhancer.Enhance.main(Enhance.java:51) Caused by: java.lang.reflect.InvocationTargetException 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.appengine.tools.enhancer.Enhancer.execute(Enhancer.java:74) ... 2 more Caused by: java.lang.IllegalArgumentException at org.objectweb.asm.ClassReader.(Unknown Source) at org.objectweb.asm.ClassReader.(Unknown Source) at org.objectweb.asm.ClassReader.(Unknown Source) at >org.datanucleus.enhancer.asm.ASMClassEnhancer.getClassNameForFileName(ASMClassEnhancer.jav>a:272) at >org.datanucleus.enhancer.DataNucleusEnhancer.getFileMetadataForInput(DataNucleusEnhancer.j>ava:727) at org.datanucleus.enhancer.DataNucleusEnhancer.enhance(DataNucleusEnhancer.java:525) at org.datanucleus.enhancer.DataNucleusEnhancer.main(DataNucleusEnhancer.java:1258) ... 7 more

Thanks in advance.

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