VMS Help FORTRAN, Error Messages, Compilation Errors, DBGOPT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  SEVERITY:  I

  MESSAGE TEXT:  The NOOPTIMIZE qualifier is recommended with the
  DEBUG qualifier

  EXPLANATION:  Optimizations performed by the compiler can cause
  several different kinds of unexpected behavior when using OpenVMS
  DEBUG.  For more information about compiler optimizations, see the
  Compaq Fortran Performance Guide for OpenVMS VAX Systems.