We are upgrading to a much more powerful game server tonight. It's scheduled for 3am Eastern Daylight Time (UTC 7am). The game itself will download and run without a problem, but account registration and login (and associated functions like achievements and multiplayer) will not be available during the upgrade, which shouldn't take more than an hour. We apologize for the inconvenience, but it'll eliminate problems that some players have had over the past few days, and ensure a solid platform for the future.
thanks
Dave