ram1009: UPDATE: I've found my own tutorial. I thought I knew what you wanted me to do but I wanted to be sure. Correct me if I'm wrong, but you're asking me (us) to delete our complete internet history, including passwords and cookies just so I (we) can buy a game from this site. Is that correct? If so, does that really seem like a reasonable solution? BTW, I just tried again and the problem persists for me.
Look, clearing the browser's cache is often required to solve all sorts of issues, not just on this site, everywhere, so yeah it's a very reasonable solution. Clearing the browser's cache also keeps the trash from pilling up and take up space, so you should probably do it from time to time anyway.
And you don't need to clear your history or passwords, you can be selective about what you delete, so maybe try flushing out just the temporary files and maybe cookies and that will probably do it - you'll get all of those back the moment you reload the relevant pages anyway.
You say the problem persists, but did you cleared the browser's cache or not ?