VMS Help LBR Routines, LBR$DELETE_KEY, Condition Values Returned  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    LBR$_ILLCTL        Specified library control index not valid.
    LBR$_KEYNOTFND     Specified key not found.
    LBR$_LIBNOTOPN     Specified library not open.
    LBR$_UPDURTRAV     Specified index update not valid in a user-
                       supplied routine specified in LBR$SEARCH or
                       LBR$GET_INDEX.