Sounds like a codec problem. If I remember correctly, the early Narutos were encoded with DivX3 (at least that's what my FourCC labels are). Download the latest versions of DivX (www.divx.com) and you should be fine.

The later versions of Naruto are encoded with XviD. I use Koepi's Binary Build.
Get it here: http://www.koepi.org/