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

  ERROR:  A private value is one that is not imported or exported.  In
  the  context  marked  by the message, only a private value is legal.
  Situations where this message is issued include:  defining one value
  in  terms  of  another;  and  arguments to functions.  In general, a
  value must be private when the  compiler  must  know  the  value  at
  compile  time.   Exported  values  are disallowed in these contexts,
  even though  a  value  is  present,  because  that  value  could  be
  overridden at run time.

  USER ACTION:  Change the value to be private.