Recent password change, can't create new threads
H'mmm ...
Thinking out loud, I'm assuming you're logging in to your desktop with the new password - I think you have to, because the password is stored in the RPoL database, not the local browser, so even if the browser was helpfully supplying the old password, you'd fail login.
I suggest clearing cookies, temp files, history etc on the browser (I know I've had problems with IE before not clearing up even when I've set it to do so by default when I close the session) - just in case there's some odd setting that's lurking in the background that's not getting refreshed.
Also log out entirely from RPoL on the phone first, just in case that's causing something to cache (the phone holding a setting on RPoL that the desktop then can't reset). Just a guess, but can't hurt.
Cheers,
Skald