Problem with Effects/Fades, in 6.5

[Mountain Goat]

Hi

I've been editing quite a lot of video lately using Premiere 6.5, and am experiencing a bad problem that occurs when the clip is faded, or effects are applied to the clip. The clip appears to be badly interlaced for a few seconds while the effect is in action. For example, during a fade, thick black and white bars appear across the clip. When I use keyframes to adjust a clips brightness, these bars appear again, although not so thick, while the brightness is changing. When I use the transform filter to move the clip, or adjust its size using keyframes, all sorts of horrible lines and distortions appear. I am using Mpeg1 Clips, which are not interlaced, and have played around with various settings, but can't find anything that fixes the problem. I've attached some stills showing what happens to a clip when it is adjusted using the transform filter. (Clip with the trees is in the background, behind the layer of grass in the foreground, trees are zoomed in and moving across the screen behind grass, grass moves downwards and off the screen as trees zoom out and centre on screen.)
It would be great if anyone could suggest anything to fix this problem.
Thanks.
MG

[Marc Peters]

Have you rendered the timeline?

[Mountain Goat]

Yes, these stills were taken from a exported video. The funny thing is, this interlacing, or whatever it is, changes form, before the time line is rendered, after the timeline is rendered, and after the video is exported.

[Marc Peters]

Are you exporting your video as progressive (not interlaced and no de-interlace filter applied).

[Mountain Goat]

I think I solved the problem, I was exporting the video as progressive using Adobes Mpeg encoder, but when I just exported as progressive to AVI, and the clips came out fine. I think from now on I'll use a specific Mpeg Encoder and just export everything out of Premiere in AVI, as I've had problems before with its Mpeg encoder.
Thanks for your help.