shrug i dunno... i dont work in premier but inported .avi with an alpha channel (um, unmatted ??? in after effects i cant remember, i get a dialoge that asks if i want to import the subsequent .avi matted, unmmater or ignore and i get a clean alpha)) but thats after effects... seems strange both adobe products support .avi differently... but i suspect, with no experience with your version of premier and your computer that, it would seem to me a premier issue to me.