I have the same problem when I use the write-on effect is Premiere Pro CS4. No matter what I do, de-interlace, Upper field, lower field, progressive scan, On the original, reveal the original, on transparent; the result is always jagged line. I spent hours preparing my sequences which looked fantastic in the preview panel, but once I rendered them out to DV AVI I got this horrible interlaced appearance of the line. I am pretty sure I am not doing anything wrong and I have no other problems with Prem Pro. Very frustrating.