m4v is a Quicktime file if I'm not mistaken. You probably want to convert it to an .avi or at the very least an mpeg. This might help.
http://club.cdfreaks.com/f59/how-convert-quicktime-m4v-mpeg-m4v-avi-m4v-dvd-vob-178052/
Sorry, this might work better.
http://www.download.com/Pazera-Free-...html?tag=mncol