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

 the user-mode exit handler list is corrupt

    Facility: DEBUG, VMS Debugger

    Explanation: While walking the list of user-mode exit handlers,
    the debugger detected a forward link which pointed to an
    inaccessible exit control block.

    User Action: Check for a call to the SYS$DCLEXH system service
    that specifies an illegal exit control block argument. Also
    verify that exit control blocks are not getting corrupted later
    in the program.