This is a common thing where AVI turns into x-msvideo when you upload it to AW, it depends on what plugins your converting software is using or something like that. Try using a different programme to convert it and see if that makes any difference.
AW directed me to this help centre article last time I asked.....not really that much help but have a read if you want.... http://www.adultwork.com/LKBA.asp?A=47
AW directed me to this help centre article last time I asked.....not really that much help but have a read if you want.... http://www.adultwork.com/LKBA.asp?A=47