I provided the link to my campaign to a friend (the one given in the sidebar where the chat resides). He clicked on the link in IE and it allowed him to sign up and join the game.
It also locked up his system. He had to use the task manager to kill the process.
I cannot repro the bug unless I sign up with a secondary account (he refuses to return to the site...thinks there is malware or something... ). I don't want to create a secondary account just to test it...but I will if you need me to.
I've asked him which version of IE he was using...still waiting on a response. Will update this discussion when I hear back from him.