Yup- that's almost certainly your problem. If you set your date/time (and timezone) accurately, I bet the market will work for you. For me, that's what makes this problem more than a simple annoyance (a lot of things depend on the time being right). To make matters worse, I realized it's not just resetting the time to 1/1/1970 @ 4:00 PM every time it shuts down. Even when it's on, it loses about 15 minutes every hour or so.
This is my 2nd unit, and I'd return this one too, but X10 would make me pay the shipping costs (again) and, many, many weeks from now, I'd finally get a replacement that will probably have some other problem(s). I think I'm just going to consider this a $230 mistake and cut my losses. I have a friend that is a biology teacher and was lobbying the school to provide tables for every student. This was a tablet he was looking at as an option, but today, I was forced to recommend against purchasing an AirPad. It's sad, because it really does have a lot going for it.