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

 illegal length field length_value in structure reference

    Facility: DEBUG, VMS Debugger

    Explanation: A negative value was given for the length of a field
    in a structure reference.

    User Action: Change the field length to a non-negative value.