Ditto here, AppGameKit works without any hiccups on Win7 (64bit).
Some things to look out for though, is that AppGameKit uses OpenGL 2.0 and later for its Audio, 2D and 3D rendering - so whatever else you do, make certain you got the latest graphics driver installed for your system. Some very low-end and older laptops (and small client boxes) do not support OpenGL 2.0.
Also make sure your Win7 installation is up to date with all the latest patches and Service Pack 1. This may require some tomfoolery and manual installation. I had to do this on my PC back when. Don't quite remember what the solution was, but the issue was that auto-update would not work.
Apart from that general advice, if you need more help we're going to need a lot more information on your system.