Does your MFD currently have any waypoints? To get mine to work (G-Series) I had to export the few waypoints that the previous owner had left on the MFD onto the CF card. Then using my PC I took my waypoints that I had converted to .rwf format and saved them to the "archive" file that the MFD had created. (Important: there can be only one archive file on the CF card). The MFD was then able to import all of the waypoints when I re-inserted the CF card.
The only thing that ever works on an old boat is the owner.