Downloading an update?

When I try to login to the game, it brings me to a screen to download an update to the game, which I don't think is supposed to happen, It says it's trying to update to 4.0, which is not what I want. I have the "new" WoTLK client that I'm using. It brings me to a patch screen, and doesn't let me install any patch. I don't know how to fix this, and I've already reinstalled it and everything.

Do not update your client! Log in with your username (not email).

Thanks! It works now, such an easy fix.