MediaLab and DirectRT use the Windows Media Player video engine to play videos--even QuickTime videos. Try playing the video in the Windows Media Player on its own and see if you get the same result. If so, try downloading the 3ivx codec from www.3ivx.com/download/index.html. This codec should allow the WMP to play your Quicktime videos properly.

Also, if you go this route, make sure you turn *off* the enhanced video option on the MediaLab preferences menu.

Hope that helps,
Blair