Playing CD burnt on PC on my Powerbook?

Recently I burnt several avi files ( and an mkv file) onto a memorex dvd-r using Roxio drag to disc on my winxp laptop.
Since then I’ve had no problem opening the files using another winxp laptop machine. However, when I try to open them in my powerbook I run into problems. The dvd appears on the desktop and I can see the folder containing the files but they will not play. I double click and nothing happens. Same results when I try to open the files with vlc. Also, the file information is just incorrect. For instance, a ~600 mb file is listed as 73 mb for whatever reason.
Would anyone know what the problem may be?