In my previous post, I mentioned a customer who had problems reading a course DVD. To read that post, you can go here: InstallShield doesn't like Full DVDs
I found out that the problem was not caused by a DVD that was too full. It was actually the result of a bad DVD burner drive in my duplicator. As a result, I don't have to modify my definition of a disc being too full. So, the classic symptom of a CD or DVD being too full is still that "the InstallShield installation program will crash during the loading of the installation".