/sys$common/syshlp/helplib.hlb UIL, Compile Time Errors, SINGLE_OCCUR  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  ERROR:  You have specified a particular clause more than once  in  a
  context  where  that  clause  can only occur once.  For example, the
  version clause in the module can only occur once.

  USER ACTION:  Choose the correct clause and delete the others.