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

 opcode opcode_name is unknown

    Facility: DEBUG, VMS Debugger

    Explanation: The opcode opcode_name specified as a command
    parameter is unknown to the debugger. It may be the case that
    an opcode synonym has been specified which is not recognized by
    the debugger.

    User Action: Specify a valid opcode or specify an opcode synonym
    that the debugger recognizes.