If you can't download the map or access the support page then I suspect you may have an issue with your system or ISP. Never had an issue downloading maps and I can access the support page. Have you tried a different browser?
MapSource should you wish to use it is still available but as I've already pointed out the issue only seems to affect certain routes and many folks report no issues using BaseCamp despite the warning given in that FAQ. If you want more advice on a 665 with Basecamp there is a Zumo forum here www.zumoforums.com
Here's a work-around solution to Basecamp waypoint searches. If you, like I, have had problems with computer searches, here's a bulletproof solution:
1. Have Basecamp open and running with your GPS connected.
2. Start Mapquest.
3. In Mapquest, look up whatever address, etc. you want to find. It will pop up with an icon.
4. Follow these steps exactly:
5. RIGHT click the icon.
6. LEFT click "What's here?"
7. At the bottom of the page, you'll see some GPS coordinates. LEFT click those coordinates.
8. Over on the left you'll see those coordinates. COPY the set of coordinates that look like this:
9. Switch over to Basecamp.
10. At the top of the page, LEFT click "Find."
11. At the bottom of those choices, LEFT click "Locate Coordinates."
12. PASTE the coordinates you got from Mapquest into Basecamp.
13. Click "Recenter."
14. Click "Create Waypoint."
It's unfortunate that Basecamp is so often incapable of working well, but this works. Actually, it's only a few more steps, but I chose to make this procedure as clear as possible.
Hope it helps.