I've recently started having this issue on my ATV2, where I am regulalrly (multiple times a day) asked to verify my payment information. The message says something like, go to your computer and verify your payment information.
I log into the iTunes Store, access my payment information and my 3 digit CCV is missing. I enter it, and everything plays nice for a couple hours. Then I am prompted again, I go back and the CCV is missing. It's been happening for days.
I've searched the forum, and it looks like others have had this issue occur previously. I've tried several of the "solutions" to no avail, including removing my credit card from my account & re-adding it, removing the credit card from my account and adding a different one, unplugging the apple TV, confirming my ccv, etc.
The odd part is that I am not having issues playing content purchased from iTunes.
The frustrating part is that I cannot send any Airplay content to my ATV if the prompt is on the screen. I have to click "OK" to dismiss the notice, then initiate airplay which is a pain.