Backend doesn’t work

I tried to update my wordpress installation to 2.3, and unfortunately, something went wrong. My backups are dead (empty) and I haven’t got a clue what to do. The main site loads, but I can’t log into the backend as admin. When I try logging in as admin, it just gives me an empty login page again. When I make a new account, I get an error that looks like this when I try to log in:
http://myskitch.com/samuraibsd/erratum5__profile__wordpress-20071013-004238.jpg

What’s wrong? Is it fixable? Thanks for any and all help