I had problems trying to log into Diablo III. I could enter my password, but when I entered my Authenticator number, I got Error 14009 Can't download Agreement. I tried:

1. Logging into the American and Asian regions.
2. Deleting Blizzard Entertainment and Battle.net folders in /Application Data.
3. Logging in on my husband's computer to the American region. Got no agreeement.
4. Changing my Battle net password.

At one point my password stopped working, and I started getting Error 14404 after entering my password, but this went away once I tried to log in on his computer. I then tried:

5. Logging in on my husband's computer to the Asian region. Got an agreement, agreed to it, heros all present :) Was then able to log in on my own computer.

Blah - weird. Took an hour and a half to get this sorted - all of my playing time! :(