Bug with your website
There seems to be a bug with your website. When I first come to the site and click on the Forums link it goes to the forums page and then immediately kicks me back to the main photopost page. Upon a second round of clicking it lets me into the forum. This only happens if I am logged into the forum with the "remember me" cookie.
Also once in the forum if I click on the User CP link it kicks me back to the Photopost homepage.
I've confirmed this problems in Both IE and FireFox.