I think it maybe that there are many avi subtypes . http://www.petesvideo.com/vidDVformats.htm It may happen that the particular subtype codec used to create the avi is not available or supported by Poser . If you have a video editor or converter, you could try loading it and converting into another format (eg wmv) and then back again into avi . http://www.gold-software.com/multimedia58-180.html