[mdr-users] Problems instantiating my own metamodel

Hello,

I'm using mdr-standalone and I have a problem instantiating my M2 level model,
which is not UML but my own metamodel.

rulesPackage is instance of MofPackage named "EAIRules" which is the
root package of the model. The thrown exception holds no more information.

org.netbeans.api.mdr.CreationFailedException: Cannot instantiate package because
of unexpected exception: org.netbeans.mdr.util.DebugException
        at
org.netbeans.mdr.NBMDRepositoryImpl.createExtent(NBMDRepositoryImpl.java:484)
        at
org.netbeans.mdr.NBMDRepositoryImpl.createExtent(NBMDRepositoryImpl.java:287)
        at
org.netbeans.mdr.NBMDRepositoryImpl.createExtent(NBMDRepositoryImpl.java:275)
        at
co.edu.uniandes.eairules.mdr.processor.EAIRulesPackageHelper.createExtend(EAIRulesPackageHelper.java:205)
        at
co.edu.uniandes.eairules.mdr.processor.EAIRulesPackageHelper.loadEAIRulesModel(EAIRulesPackageHelper.java:230)
        at co.edu.uniandes.eairules.main.Main.main(Main.java:39)

This  is my code:

      rulesPackage = ( EairulesPackage ) repository.getExtent(name);

      if(rulesPackage == null)
      {
         rulesPackage = ( EairulesPackage ) repository.createExtent( name,
getRulesPackage() );
             }

The method getRulesPackage() return the "EAIRules" package. The topmost package
of EAIRules metamodel.

Please, can you help me ?