I'm completely new to the Apple TV, but know my way around OS X. I've spent hours getting this thing to work as it should, but there's still a few things that I just can't get right.

First. In iTunes, my US iTunes Store account works and I can watch all my purchases. In Back Row nothing plays and the only message I get is "Your Apple TV is not authorized to play this content". What gives?

Second. I've hooked my MacBook Pro to a brand new Samsung 37" LCD through a DVI to HDMI cable. Back Row looks good, but if I try to rent any movies in HD, it just tells me that my TV hasn't got HDCP and cannot play the content.

I've googled around for hours without finding any good solutions to the problems. I'd be grateful for any suggestions.