Your problem may have nothing to do with the built-in account creation feature. There is a reported bug that does not allow some valid GMail accounts to sign in from the 770. To test it out, see if the account you created can be accessed on a PC. Since some accounts created on the 770 do seem to work, my guess is that you are running into the authentication bug. Another test would be to try to create another account on the 770 to see if it will log in/authenticate.