Help! iTunes will only sync purchased videos..

My mom often imports some of my music and videos to iTunes on her Dell desktop. For some reason when she syncs her iPod touch (4G), only purchased videos will sync, like some movies and tv shows that I purchased. Videos that I uploaded from my DVD collection will not. I can't think of what could be wrong because they are all in mpeg-4 format and these same movies sync just fine with my iPhone. Does anyone have an idea of what could be wrong? Thanks for your help!