Library /sys$common/syshlp/basichelp.hlb Compile time errors, CONNOTALL  *Conan The Librarian (sorry for the slow response - running on an old VAX)

  ERROR - The  program  tries  to  assign  a  value  to  a  user-defined
  constant.   Remove  the assignment statement; once you have assigned a
  value to a declared constant, you cannot change it.