Error logging into Pandaria (Conversion Error)

For some reason every time I input my account info, it gives me the error "this account needs to be converted to a battle net account[Click here] or go to "www.battlenet.com" (something along those lines) to begin the conversion process.

Any ideas on what is the problem? I used my regular login info and it was working fine a few days ago (ALSO IT WORKS ON THE CATACLYSM SERVER BUT NOT PANDARIA)

Having the same error. By the way, I can connect from a friend's client (another computer and ISP) but i cannot from my own, i get the same error. (Did not try wotlk or cata)