I can't sign in to view billing info

I'm trying to rent a movie, but iTunes asks me to first confirm my billing information. I introduce my apple ID and the correct password and nothing happens. I just get the same window again asking for ID and password. If I enter the wrong password, I get an error message. But when I enter the right password, all I get is the same window again. I've reset the password a few times, but it never works.

In short, I can sign in into iTunes, but I cannot sign in to view account info, billing info or other things I need in order to be able to rent. Help!