Sigh... Michael, The problem that you are experiencing with the black video is a result of a crappy MPEG decoder hanging out on your system (probably from WinDVD). If you want to fix it, prepare to roll up your sleeves, cause its going to get messy. Google an app call Graph Edit and download it onto your system. Next, Google another app called RadLight DirectShow filter manager and download and install it. Once both apps are installed, open Graph Edit and drag/drop one of your MPEG clips into it. Graph Edit will build a DirectShow filter graph to play the MPEG clip. Take special note of what MPEG video decoder is being used. Open RadLight filter manager and navigate to the DirectShow filters, then to the MPEG decoder listed in Graph Edit. Set the merit value of the decoder to low. Now navigate to the MainConcept MPEG video decoder and set its merit value to preferred. Once both values are set, reboot your system. Open Graph Edit again. Drag/drop the MPEG clip into again and let it build a filter graph. If Graph Edit now shows MainConcept, your problem with black video are resolved. If it shows some other MPEG video decoder, go through the above steps again until you finally get the default MPEG decoder to be MainConcept.
Now that you've fixed the black frames problem, you've just opened the door to others. You really shouldn't be editing MPEG files, they just don't edit well. Finish this project and work with AVI files in all future projects (you'll have fewer gray hairs).
Mitch411