I'll give you a hint.. if you haven't changed anything.. it is your username, password, or security key is incorrect. The wizard almost always does the rest right for you.
On the pp_checkout_failure page.... there is no local checkout action available for the express action. I could add a local checkout for direct Paypal payment, but is that really going to tell me anything?
Anyway, it is working now... just for future reference... I'd like to know the proper procedure..