How do you get the variable id for a file? I am looking at the example for batch update(Batch Update Card Variables) and it gives an example for getting a vault variable id. When I tried to do the same thing using a file instead of vault but it gives me the error "Unable to cast COM object of type 'System.__ComObject ' to interface type EPDM.Interop.epdm.IEdmVariableMgr5." I am getting this error when