[Users] MPI thorn doesn't output error messages

I am seeing this error message from thorn MPI:

Running configuration script for thorn MPI: MPI could not be configured.

CST error 1: -> Configuration script for thorn MPI returned exit code 5 (no error message)

Finished running configuration script for thorn MPI.

That's not good enough, I really need to see either an error message, or at least a line number. The previous MPI configuration script echoed all commands to stderr, so that it was easy to see where things fail.

-erik