[BCooperman]

I have begun teaching online courses at my university and have come across a problem no one seems to be able to help with. The videos work perfectly for many of my students, but in some cases instead of bringing up a separate box with a visible control bar at the bottom clicking on the link brings up the video in a much larger size image with no toolbar visible. In these cases the video is very slow and often seizes, to the point of being useless. More "savvy" students have told me that in these cases they download the videos and watch them painlessly. The odd thing is that the problem varies from place to place: I can watch the videos easily from home where I have Comcast cable and from many sites on my campus. But there are buildings on campus where even hard-wired connections won't work. I have tried to access the videos from many other sites with mixed results.
The videos are created by camcorders, imported using Imovie, edited with ScreenFlow and then exported as hinted QuickTime videos.
Any suggestions would be much appreciated.