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

 invalid expression for operand number operand_number

    Facility: DEBUG, VMS Debugger

    Explanation: The specified operand was not correct for this
    instruction.

    User Action: Please check the documentation for the correct
    operands for this instruction, and re-enter the instruction with
    the correct operands.