[danielf]

I don't know if this is any help (and I don't know how you could embed the video), but you could try loading the stuff beforehand and testing it (always a good idea when it comes to presentations).

Alternatively, you could consider sticking the ppt and video on a pen drive (assuming you have one), and plug that into the usb port on the machine you will be running the presentation from. That way, (I presume), it will still link to the correct path. I don't know if the usb connection will be fast enough to stream the video from though.