Portal MPR, SET Transition, Action Workflow with a Function Evaluator to copy datetime attribute to another datetime attribute

Hi,

I am trying to copy a datetime attribute to another datetime attribute within the FIM portal using an action workflow and function evaluator.

e.g. Target [//Target/TargetDate]  

Conactenate Value

SourceDate attribute.

The workflow creates fine but gives an internal error when the set transition occurs.  Can this be done?  Can you suggest a straightforward workaround if not.

Thanks,

A.