Welcome to the forum
Even if the drive is able to read -R/+R discs, this doesn't means that it is able to read everything is burned on the disc
What format is the file exactly? Is it an avi? Can you run gspot on the video and post here the picture?
Moreover, most of times, playback issues are due to a low quality disc. Try to burn a good quality disc like a Verbatim, usually this solves