From the sounds of it, since you say you can log onto the account and click on a character but it asks for a password, that's what you're stuck at. It's the character password feature of the game.
What you'll want to do is click on a character and click "Set Password" on the bottom right corner and set a character password that has to be exactly six characters long. Make sure you remember it as it will ask you to input it every time you log onto that character.
I believe that's what you're stuck on, anyway. Once that's set, you should be good to go.