I have a garmin gpsmap60csx and was having a similar problem trying to download caches. I found a solution that worked for me. The geocache website would not recognize that I had the plugin installed. (even though I did and it was enabled) When I would go to the garmin website, it would recognize it and tell me I had the latest version installed. After searching the internet for a bit, I found this solution. I have IE 11 and apparently, it was not set for geocaching.com to be displayed in compatibility mode. I did the following and now it works:
Click on tools,
click on compatibility view settings,
under "add this website" type in geocaching.com
click the "add" button
make sure geocaching.com is in the lower box under "websites you've added to compatibility view"
make sure the box "display intranet sites in compatibility view" is checked
click "close"
after that, geocaching.com recognizes that I have the plugin and I am able to download. Good luck!
