OK guys, one more try. Can you guys please log out, log in again, and check the main site to see if you are logged in still? I think I've worked out a way to get it to work now. It's working for me anyway.
I'm not too sure how well this will work though - it won't remember you like the forums do, so you'll have to log in again every time you want to use something on the main site, but it's the best I can do. I mean, I've pretty much tried everything at this point. \
Oh yeah - if it's not working, try clearing out your cookies. I know that's really annoying, but again, it's the only way it will work.