Have you found a solution? I am experiencing the same problems.. running MAC OS 9.2. Some of the downloads will launch, some (most) others will not launch. They show up with a different icon than the others that will launch. A plain document icon (sheet of paper).. I think these have something to do with the "incomplete" downloads we hear about... Still not sure but that is where I am investigating..

My MP3s that will launch show up as Quick TIme Document.. I do not have itunes. The ones that download and will not launch show up as a plain document with no other description.