This is usually just because the server for the free edition is like a second class erver, and can get bogged down. So basically if it is getting slammed with a lot of people at once you won't be able to update. Keep trying, and eventually it will work.
I remember some tweak for the original version that allowed you to connect to the main servers, which always give faster service. I will see if I can find it, and if it will still work.