I do believe that, for changing your account password to work in-game, you have to change it a certain way. Open a new tab and go to the FH website (NOT the forums!) and try the "forgot password" option on the yellow box in the corner where you'd normally register an account before the updates happened and follow the on-screen steps from there. Give it a day or two for it to reset, and then try again. I don't know if this method still works after all the updating that's been going on here, but it's always worth a try.
That's about all I can give you, hopefully it helps at least a little.