http://www.eqemulator.org/forums/showthread.php?t=31238
You have you enter the new password twice to prevent this from happening. You just changed it or was it sometime ago? Seems odd to have just changed it, entering it twice (else it wont get changed) then forget at the login screen.
May be something as simple as having had your caps lock on when you were changing it through the UCP/LS password change screen. <shrug> Worth a shot.