"Finish creating your account by choosing your new nickname!" - I'm stuck in an infinite loop.

I have a Gravatar account with three e-mail addresses linked to it. It appears (as I just noticed) that I had actually created a separate account with one of those e-mail addresses in November 2007 (just shortly after Gravatar was acquired by Automattic). Nevertheless, I am able to add that address to my new account, but it gets deleted after a short while. Meaning: it was in my account 20 minutes ago when I added and verified it, and it was still there 10 minutes ago, but it's gone now. No cookie trickery either, because I'm checking this in two different browsers (FF3 and Safari).

Something must have gone wrong, because when I (accidentally) log in to en.gravatar.com with that one email address, I get stuck in an infinite loop that keeps taking me back to the page that says "Finish creating your account by choosing your new nickname!". No matter what I click (log in, reset password), I am taken back to that page. The only way out is to delete certain cookies from the wordpress.com domain (deleting gravatar.com cookies has no effect). I'm guessing something went wrong with my account when gravatar and wordpress.com accounts were merged.

I just spent about an hour trying to figure out what was going on and writing this down. If someone from Automattic could PM me, I will be glad to give you the email addresses in question and any other info you may need so you can check it out (and help me out of this infinite loop).