To anyone more technically gifted than me :

Get this message when I try to run the tutorial files _ same for all four that I've downloaded so far.

Error - 2041 : An invalid sample description was found in the movie (WAMP_03 - OrgFileNaming.mp4).

Can you help?
Bob.

If you are a Windows user, try VLC Player

Links and answers are to be found on the FAQ

Thanks Chris. All OK.
Bob.