Two days ago I helped a friend of mine to install MM on his own N770, and it gave same error... Double & triple check the URL, after that it should work. I made an installation from scratch and it worked almost flawlessly. Sometimes Google's server doesn't like your map request, but after two or three retries it works.
Are you sure not to have any problem on your MMC? I have no other hints, sorry. Mine works perfectly from MM1 on IT2005...