Unexpected error trying to verify external routine <str>.

  Explanation:  An  unexpected  error  occurred  while  trying  to
  verify  the  specified external routine.  A second error message
  is displayed indicating the type of error that occurred.

  User Action:  Delete and redefine the external routine, and  try
  the verify operation again.  If the error persists, contact your
  Oracle support representative for assistance.