30gb Ipod 5th Generation - Can sync music not movies?

I was thinking about going back to Apple for all our mobiles and this got me rummaging through my old desk drawers to find my old Apple appliances. I have a relatively unused and new dare I say iPod 30gb that I used to use. It works fine though when I look to sync via the iTunes software (windows) it only does the music and says the file format for videos are incorrect (.MP4). The movies shows in the library all well and good. What am I doing wrong? I'd like to sort this before I make a venture back in to the world of Apple.