I am having this problem also, and I still haven’t found an acceptible workaround. I usually do my editing in After Effects, but for this project, I decided to use Premiere. I need to end up with a 720×480 WMV, but Adobe Media Encoder is yielding janky video that looks like it might be as good as 360×240. I have CS3 on an older machine, but I can’t get the project to load. Very frustrating.