The autoupdater runs on a different ISP than the game servers do. The WEB page download is the same file the autoupdater grabs.
However, if you are on Vista and the game is installed in the "Program Files" folder, the autoupdater will not work. This is a feature of Vista. Nice, eh?
Outside the "Program Files" folder, the autoupdater works fine. Just FYI, never install anything in the "Program Files" folder of Vista or Windows 7 for that matter. Your computer and applications will be much happier.
Now, if you have already installed outside the "Program Files" folder and it still hangs on the terrain update, I would check the Internet path (
www.pingplotter.com) to 70.87.104.98, which is the server where the files come from.