Not sure if any of you are still having trouble with this but, this is what I did –
The link should take you to a page about the authentication system. Scroll down the page and click the “Problems Receiving Authentication Email Please click here for assistance.” link.
It’ll take you to a page where you can either reset your password, or disable the authentication system for your account. I have no idea how to enable it once you’ve disabled it though.
http://eu.support.guildwars2.com/app/answers/detail/a_id/9192