After more investigation, we've found that the Atlas Games website was indeed hacked, and malicious code inserted into our files. We've cleaned out the code, and disabled our forums, which we suspect was the point of entry. The forums will remain disabled until we can perform an upgrade to them next week. We're very sorry for the inconvenience.
This malicious code was designed to open up another site in the background of visitors' browsers, and download viruses to their computers. In particular, it seems that a "Trojan" virus has infected the computers of several of the users we've been working with on this. This Trojan is evading AVG, Norton Antivirus, and Windows Defender. However, Microsoft Windows Malicious Software Removal Tool and Windows Live OneCare are both able to identify and purge it.
So, to anyone having trouble I'd suggest you run one of those two programs on your system, and update your virus detector.
Again, we're very sorry for the trouble. Thanks for your patience everyone, and our special thanks to those who helped us ferret this out!