They weren't real specific (surprise surprise) but quoted the rule that "You may not use the Apple Logo or any other Apple-owned graphic symbol, logo, or icon...."
Almost. In addition to an image of the screen, we superimposed it on top of the image returned from NSImageNameComputer, which grabs an icon-ish representation of the user's computer model (e.g. it produces an iMac image when run on an iMac), and that often includes an Apple logo. We also superimposed the icon of the selected app on the Mac, which was often iTunes or another Apple app. One of those is what they didn't like.
