MECHNSM

I have not used my Magellan Explorist 110 in 7 years. When I have my GPS unit properly attached to my laptop as indicated on the Magellan screen, all I see on my laptop screen to click on when I have opened a cache is "send to Garmin". I downloaded Garmin software, but resulting message when I try to send cache to my GPS unit is that my device is not compatible. Please tell me what I need to do to send caches to my Magellan. Thanks!