After reading some more, I think I've figured out what the problem is. I tried browsing to the URL I posted and I get a page that says 'Due to ongoing maintenance, this page is currently unavailable. Please try again later'. I tried browsing to another similar link in another thread, and it was blocked by my employers firewall because it falls under the category of games. I figure it's one or the other issue causing my problem.

Is there a way to log in without using html traffic? Another type of launcher perhaps?