Classic Ipod 80GB won't play video/movie files

I have a few videos that were made as AVI files. I converted them (i thought) to MP4 Files, which have an apple quicktime logo. I enabled the sync movies to ipod in the settings/preferences,but after i sync the ipod, this window appears and states, can not sync movies or videos to ipod, wrong file.:o

I thought Ipod can play MP4 files. what am I doing wrong? Thanks you for any help.:slight_smile: