GPS, custom Google Maps and Firefox and Adobe woes

One of the features I wanted to have on this GPS was that I could upload a custom map from Google My Maps. Well, I don't know how or something is wrong. I had a map with six points on it, and I followed the directions in the video that I posted the blog "GPS - finally got one" on the 17th, using http://www.takitwithme.com/ Once I put the link to my map in the space and told it to get my map it said at the bottom it was retrieving my map but never did quit spinning. So, I told it to upload to the GPS and got the error "fatal error. File Path: String Stream line 1, char 1. message: invalid document structure." I thought it might be Internet Explorer, so I used Firefox. That time it still didn't retrieve my map. When I clicked for it to upload, it took me to Garmin to get the app it wanted. That process said it was successful. But I couldn't ever get the custom map to upload. I got the same error as with I.E. Searching around I found somebody posted on a forum or something that they couldn't get that feature to work with multiple points. I went back and did it with a start point and one end point, and the same results. It never said it retrieved my map and I go the same error message.
I went to Garmin's site for some kind of help and nothing. Nothing is in the startup booklet about it, and I can't find it in the programmed help section in the unit. Nor does there seem to be a user's manual you can download anywhere. But yet the stats on this unit says that you can upload custom maps. Crap!! I hate this!
I'll have to call Garmin tomorrow and see if they'll tell me how, but I bet they don't do that kind of support. I also tried to just manually type in the coordinates but the keyboard is not active. I couldn't even find the coordinates on Google Maps -- had to look somewhere else to find them. Grrrr!!

Through all this process Firefox said it wanted to upgrade. So, I said okay. It upgraded me to Version 3.6.10. Then it said I had to upgrade the Adobe -- whatever. So, I did, and now every time I start Firefox I get one of the cursed Vista warnings, "User Account Control - Adobe DLM, User Account Control helps stop unauthorized changes to your computer"!!! Then the Adobe Download manager screen is up and I have to close it before I can use Firefox!! Soooo muuucchhh Bullll sh*t!!
UPDATE AT 1:39 A.M. About the Adobe DLM - I have no idea what DLM is other than it's Flash, I guess. Nor do I know if I need it or if not, how to get rid of it, if I even should. I didn't see it in the Add/Remove Programs nor did I see it in my Programs list, even though it had just been installed! But I did find where to turn off the User Account Control and that seemed to remedy all the frickin' authorization pop-ups. God, I hate Vista.