Library /sys$common/syshlp/dbg$help.hlb DEBUG, Messages, ILLFILPTR  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 file variable points to invalid file descriptor

    Facility: DEBUG, VMS Debugger

    Explanation: The file variable references a file descriptor that
    cannot be read, is incomplete, or points to a file that is not
    open.

    User Action: Correct the file descriptor.