Did you use the procedure for activating an existing account? It's slightly different from the new account method:
http://www2.adult-fanfiction.org/forum/index.php/topic/29595-existing-users-logging-in-for-the-1st-time-in-the-new-system/
We have the account pen name as GamerChick, and the email address is the blackpanther address at gmail
If you've done that already, what you may need to do is clear the deck a bit. Log out of AFF, even if you don't think you're logged in. Then clear your browser's history, close the browser all the way, restart the browser, and then try logging in to AFF. Sometimes you need to refresh and reset a bit.