There are some known issues with Powerpoint and attempting to use presentations across platforms like this. Some of it has to do with the original file types inserted. Macs use Quicktime by default while Windows machines don’t, so that could be a problem. In general, if you create the presentation on a Mac, you’re going to have problems on Windows, while the reverse is also true. With high probability any two machines are going to have a different library of audio and video codecs to work with.
Actually, I have FAR fewer problems with Windows-based Powerpoint files presented on my Macs... I get sent Powerpoint files all the time created under Windows - that almost NEVER fail to play - media included.