This window popped up when I installed the latest update to Aperture 3:

Destroy all 3ivx codecs

And sure enought, the linked support document tells you to purge that 3ivx codec from your system. Where did it come from? FlipShare.

And so the component is gone, and Aperture is noticably more responsive. And the legacy of that lovely little Flip cam fades a little more into the past…