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

 cannot set break or trace at address address_value

    Facility: DEBUG, VMS Debugger

    Explanation: The user has requested that a breakpoint be set at
    an address that is either non-writable, in Debug, or invalid in
    some other way.

    User Action: Correct the address and reissue the command