BAPI gives error through JCo and works fine with JRA

I am trying to execute a BAPI - BAPI_PROCORD_RELEASE through MII. When i execute it through JCo it throws an error "Function not possible for the object" and when i execute it through JRA connection it runs fine. Can somebody help me why does this happen, i checked the request xml of both and found it to be same

Thanks

Anant