Actually, I take that back.
It takes a screenshot no problem if I'm on the home screen. But if I open up my Direct Publisher app, and try to take a screenshot, it just says "Screenshot Ok", but doesn't show a screenshot. The image area has nothing in it.
But, if I exit the app, go to home page, and say screenshot, it works.
So not getting the point of that option either.
I'm having the same issue and I'm SDK. Takes the home page but not in the app.