problem of loading maps on the gps Dakota 20

I installed maps from Openstreetmap site on the SD card of my gps Dakota 20, following the procedure described on the site “Installing the maps on the GPS”.
I also dowloaded the Javawa software to manage cards. Using Javawa, I see the different cards on the SD.

But when I open the gps, the maps are not visible.
DO you have an idea what going wrong ? Thanks

Probably another map has the same FID. Change the FID of the map . When I remember it right, this can be done with gmaptool.

what is gmaptool ? Is it a software to manage maps on the gps? Same as Javawa ?