Premiere 6.0--blank video + no previews (codec problem?)

[tartanshell]

I finished a video in Premiere 6.0 the other night and was planning to export it. I closed Premiere, got online to refresh my memory on how to export, and mistakenly thought I needed to download the Panasonic DV codec in order to follow a tutorial.

So, I downloaded and installed the Panasonic DV codec, but when I opened Premiere, all of my clips were gone! They were not on the timeline or in the bin. After messing around a bit and trying to solve the problem in a number of ways, including using an auto-saved version of my project and also uninstalling the Panasonic codec (neither of which worked), I finally discovered, using GSpot, that the Lagarith codec, which I had used in VirtualDubMod to make my .avi clips, was missing from my computer! I re-downloaded and installed it, and my clips reappeared as if by magic in Premiere.

BUT, now I have another problem. My project had been set up as follows:
Editing mode: QuickTime
FPS: 24
Preview codec: Motion JPEG-A

I had created my clips, following the AMV tutorial, using AviSynth in VDubMod and then saving them as .AVI (with Lagarith as the compressor) and importing into Premiere.

This had worked fine for me for this project and in the past. Now it doesn't want to work anymore. While my clips show up fine in the source window and when I double-click a clip on the timeline to bring up that individual clip in the popup window, they do not show up (it's just black with an X in the corner) in the project window.

I switched my project settings to Video for Windows and tried the Lagarith codec for previews. When I did this, my clips showed in the project window when I hit 'play' but, when I tried to render/build a preview, it was just black video again. Same thing happened using the Cinepak codec. I downloaded two MJPEG codecs and installed them (one was the trial version of the Picvideo codec recommended in the AMV guide). With the MJPEG codecs, the project played fine when I pressed 'play,' but when I tried to render/build a preview, I got black video with a little line of dancing green squares.

I have also tried creating a new project and importing my old project into it, since I read that Premiere sometimes fixes things when you do that. It didn't work--the exact same problems were present in the new file. (I've also tried restarting my computer and hoping for a miracle, without success.)

I'm guessing this is a codec problem, but I have absolutely no idea how to fix it! I've looked online on various forums (including this one) but can't seem to find an answer. I would like to a) be able to render/build a preview so that I can make sure my vid looks good before I export and then b) export as a .AVI file using HuffYUV as the compressor, so then I can get it ready for online distribution using VirtualDubMod.

Any help would be greatly appreciated! Thanks in advance.

[Scintilla]

Do you have "Recompress" set in the project's video settings?

And if you try converting one of your clips to uncompressed RGB, does that make any difference?

(I'm wondering if this might be a colorspace issue...)