Before you login, please read the following so you can restore your ability to browse the forum if your login fails.
If you do try and login you will most likely be presented by a blank page, and any subsequent visits to pages on this forum will cause the same thing to happen.
If this happens to you, you need to delete the session_id cookie for forum.folding-community.org, the name of the cookie is phpbb2fah_sid, then restart your browser to make sure.
As long as you remain as a guest user, you will still be able to browse the forums, and you can track the progress of this problem in this thread:
Folding-community.org :: View topic - Anyone had issues getting to the forum lately?