That’s because it’s a different codec! CVID is Cinepak and IV41 is Indeo 4, which comes bundled with most Windows PC’s. DIV4 is Divx 3 fast-motion. Usually divx 5 can handle it, but not always. If it fails get the divx 3 codec here.
http://divx-digest.com/software/divxcodec.html
