VMS Help CC, Messages, UNSUPCONVSPEC  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        <Context> this argument to <function name> has a
                conversion specification "<incorrect conversion>"
                that is not supported or not fully supported on this
                platform.

 Description    The compiler has detected a conversion specification
                that will not work as specified on this platform.

 User Action    Review the documentation for this function and modify
                the conversion specification as necessary to
                accomplish your objective.