http://obsyjuju.free.fr/F1/videos/Tour%20Le%20Mans%201983%20Porsche%20956%201.avi
I'm playing in Windows Media player. You're PC is probably missing the video decompressor. Download this tool and it will sort you out http://www.free-codecs.com/download/K_Lite_Codec_Pack.htm
If you have an ipod, I think it has something to do with the latest version of iTunes. I've been having troubles with video lately as well.......
There is a great tape for sale called "In car 956", which is an onboard camera view of all the greatest tracks in the world with Derek Bell being the driver. Fantastic footage of Nuerburgring, Kyalami and other places.