If the videos were made on the iPad, Flash is not required to view.
Adobe has not made a version of Flash for the iPad.
Kappy explains why. https://discussions.apple.com/message/19446567#19446567
5 Flash Player Alternatives http://www.techshout.com/features/2011/01/flash-player-for-ipad-apps/
Top 4 browsers supports flash player on iPad and iPhone
iOS does not and can not use flash
Although there are flash enabled browsers for iOS those browsers the flash is usually converted to a format
iOS can display
ios supports H.264 mp4 mov
I suspect they have somehow associated the iPad movie format with a flash player
Tell them to download vlc it's a free open source video player that can handle most formats if not all
Get them to open your movie with vlc