I've recently had a few reports of TopStyle generating an "access violation" error when it closes, and it looks like the problem is due to some sort of conflict with the software for Microsoft's new Fingerprint Reader.
If you're using a fingerprint reader and are experiencing this problem, rest assured that the error message is harmless - you can simply click OK to dismiss it. However, I do understand that it's annoying since it apparently happens every time you close TopStyle, so it is something that needs to be resolved. I've ordered a fingerprint reader so I can reproduce and hopefully fix the problem.