008D8FC2 Invalid channel number for Guide Mode.

    Explanation:

    You tried to call Guide Mode from your program without assigning
    a number to the input/output channel.

    User Action:

    Assign a channel number to DAB$W_TT_CHANNEL. The simplest way to
    do this is to call the DEC DATATRIEVE Terminal Server immediately
    after initializing the DEC DATATRIEVE Call Interface: CALL
    DTR$DTR (DAB, DTR$M_OPT_CMD)