This might sound a bit dumb... when I upgraded from beta 2 to beta 3, my impulse ID didn't work.  It said it was invalid, even though it was the correct info.  I used the impulse option to send me my account information to double check, and even went so far as to copy/paste the login information from the email into the game login.  I was ready to give up.

The solution didn't appear until I went to make a post on the forums.  When I went to post it said I needed to validate my account.  I did so, and suddenly I was able to login in game.  The game made no indication that it was a requirement (just said invalid username/password), and offered no way to validate it.

Additionally a minor bug I found, if you are on the impulse login in game and the popup box comes up saying invalid username/password, the enter key submits another login attempt, rather than closing the error box.