After searching numerous posts and various sources, I finally stumbled across a clue on this forum. The idea came to me when I was reading about mounting an image, and then I read someone had a video error pop-up. The answer was right there, copy the videos folder over to Dark folder from the cd-rom. So I did. It worked.
I was getting really aggravated with the "get the dos version and run dosbox" answer. For some of us that isn't an acceptable solution.
B-b-but... I -don't- have the discs! ;_;
The movement seems fine and fluent until the planet comes into the screen. Then the framerate slows down drasticaly. Does anyone else experience this? Which settings do you use for CPU-Cycles?