You're just on the bleeding edge: the interweb domain name servers are still learning who you are.
Give it time...
[edit: as I suspected, after a few more retries, I got there but the vB app didn't recognize my login and gave me the "you're not logged in / permissions" alert page. It prolly depends on how you set your login cookie. For example, the way you have it now (em.com/forum) works correctly because that's what the "User CP" link in your header uses. Clear as mud now?]