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

 the host (!AC) and target (!AC) versions are incompatible

    Facility: DEBUG, VMS Debugger

    Explanation: The host kernel and target kernel versions are
    incompatible. This is usually due to different versions of the
    operating system on the host and target systems.

    User Action: Check the versions of the operating systems. Review
    the System-Code Debugger documentation to find out which versions
    are compatible.