Whenever I try to rent a movie through Apple TV, I get back a message that my account (creditcard) has expired. I went in and re-entered the info and even bought a tune just to see if it was expired. The ATV will not allow me to use my creditcard. I have removed the ATV and re-installed it with another good creditcard but still get the same message that the card has expired.
I'm having a similar experience. Only the renting option had disappeared altogether, then it appeared. When I selected and confirmed my rental, it keeps telling me that the item is no longer available.