Reboot the launcher and make sure that it is the most up to date version. My buddy had the same problem, don't press anything and see if it downloads more. Worked for my friend that way.
You might have caps lock on for the on screen keyboard
I did not have Capslock on.
I figured out that that message means my pw was wrong and it MAY BE capslock...And then i noticed what was wrong about my pw and now I can log in and play =]
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