The 'Validate' activity in Oracle BPEL gives us the functionality to validate variables again schema definitions.
When using it in your bpel process you will get a nice informative message in the 'Flow trace'.
When you're using some generic error hospital functionality you also want this message to be available in there.
First try would be, add a Scope around the activity and catch the 'invalidVariables' System Fault.
When using a getFaultString on the fault variable or after...