Well - after a number of crash logs, 36 e-mails, and more than a little detective work, the mystery of my IE7-FeedDemon bug has been solved. It turns out the an older version of Google Desktop was the culprit. Even though I had the software turned off, IE7 was attempting to load a DLL that was creating havoc with FeedDemon's attempts to use the browser.
Uninstalling Google Desktop did the trick. I downloaded the latest version from Google and reinstalled it and everything still works. Problem solved.
Kudos (again) to Bruce and Dean on the IE7 team and to Nick Bradbury for their refusal to let this situation go unresolved. As Bruce said to me yesterday afternoon: "There's no telling how many other people might run into this bug and simply give up using FeedDemon. Or IE7. Or both. We want to make sure this release works for everyone."
I love that attitude.