Dear members, When I upgraded to perian 1.1.2 it automatically moves the old version to the trash. When I tried to empty the trash it told me that perian was in use and could not emptied. For some reason the old version of perian was hindering flip4mac and wouldn't allow it to play wmv files. So what I did was restart mac os and then I was able to empty the trash. Then I was able to play wmv files on web sites. I believe that perian 1.1.1 was incompatible with the latest flip4mac. The reason I believe this, one day a avi file started distorting the picture and then crashed, os told me that the perian plug in was the likely cause. I hope that this helps.