I just started having problems with the add chapter section of MYDvD5.3 not working fast. What I found was that something happened when I uploaded the latest driver for GeForce4 GPU. I had to switch it back to the previous version to get the chapters menu going fast again.
Speaking of drivers, I also updated my Adaptec 2210 driver, and had to go back to the old one because when I captured the movie in "Better" quality, it would load the movie in my project and encoded the file to be "Best" quality, making it too big to fit. That's the pain of editing movies with MyDVD5.3, it automatically encodes the mpeg and makes it too large to use.