Can't get converted dvd to ipod

Hiya all! DVDFab converts the dvd no problem, but I can’t get the converted file onto my ipod (5,5G), it says it cannot be played on this ipod. Use the default settings in DVDFab, no prob with the prog or the conversion. using the latest version of Fab, also Vista and latest itunes.

Anyone else run up against this issue?

Thanx!