VMS Help UIL, Compile Time Errors, SUPERSEDE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  INFORMATIONAL:  An argument or callback list has either a  duplicate
  argument or duplicate reason.

  USER ACTION:  This is not necessarily an  error.   The  compiler  is
  alerting  you  to  make  sure that you intended to override an prior
  argument's value.  This  informational  message  can  be  suppressed
  using the /WARNINGS qualifier.