The 1st thing you did wrong is not buy another mac (joke) lol What are the file extensions on those files? Also, go to File>Properties & see if there's any xtra info provided. Which version of Nero do you have. I believe it's oonly the most recent version that can burn dvd's & has the mpeg2 codec, otherwise you have to purchase the mpeg2 codec separately. Also you can visit these 2 sites (they have forums): http://www.videohelp.com/ & also http://forum.dvd-guides.com/