I am partly glad it is not something really simple I missed;-) It is strange.
Once you login to WP you can access the forum. We are experiencing a separate issue on the server dealing with a download timeout on large files, but it did not seem related.
I have some one taking a closer look at our site to see if they can track this down and will report back once we locate the root cause. If anyone has any ideas it is greatly appreciated.
Regards,
Robert