Problem with VDubMod and TMPGEnc not starting up

[LocalH]

Last night, I had just captured a bit less than an hour's worth of video from my cable DVR via my analog-DV converter. I then began to put together an Avisynth script to do some cleaning and temporal smoothing (it was the Michael Larson episodes of Press Your Luck, which contains a good amount of fairly stable camera shots without a huge amount of motion, so temporal smoothing should work excellently). Once I got my script done, I happened to read about a few good Avisynth plugins (ac3source and atc). I copied those plugins into my Avisynth plugins directory, and all of a sudden both TMPGEnc and VDubMod refuse to open (TMPGEnc's window just doesn't appear, but it stays on the process list, while VDubMod crashes with a runtime error before the window even appears, with no crash log to be found). Any ideas what happened? The reason I posted this here is because the only thing that changed before having problems was that I added those two plugins mentioned earlier. I even tried removing them, nothing. My next plan of action is going to be to use a filesystem snoop to see just which files VDubMod is accessing when it crashes, but I was just wondering if anyone here had any ideas that might explain why VDubMod and TMPGEnc are both giving me fits (the only common denominator I can think of is Avisynth). For completeness, I'm running on XP SP2 Home, P4 2.8GHz, 512MB RAM. But I've not had these problems until last night.

Edit: Just ran Filemon, the only files it touches are the VDubMod EXE and the Windows prefetch information. Time to wipe the VDubMod prefetch and see if that helps - which it doesn't. TMPGEnc hasn't loaded yet, but it's still accessing Avisynth plugins.

Edit 2: Yep, it's something to do with Avisynth - I temporarily renamed my Avisynth plugins folder to oldplugins, and VDubMod instantly began working. Great, now I get the fun job of going through my plugins and trying to find the one it's choking on. Weird, since everything was working perfectly last night. Anyway, this can be ignored now, as I can move plugins back into a regular plugins directory as I need them.