you can't change your email address as far as i know, but you can change your password. all you have to do is when you log in click on the 'forgot your password?' link.

and avatar changing usually works better in gpokr, your file could be too large or not in the right format, check the help tab at the top for more information

ok, thanks :) for my avatar i needed a very small picture
(1cm*1cm). But if i understand, i have to create a new account tu use my new mail adress ?