Plugin error on 9.1.0 update?

Question

I just tried to update my Acrobat Pro to 9.1.0 and was stopped by an error message telling me the application had been altered and/or plugins had been disabled. Well, I do have the current PitStop plugin(s) installed. But I don't think I've disabled plugins in general. Searching help database and FAQs at Enfocus and Adobe gives me squat on this.
Do I really need to uninstall both PitStop and Acrobat Pro, then reinstall Acrobat, update Acrobat, then reinstall PitStop?
Yes, I can do this. No, I'd much rather someone explain to me that there's something else going on.

Answer 1

(We've been discussing this over at B4Print, here's my final rant:)
So one day back in The Day, like, oh, probably late 1994, a friend from Cupertino dropped by the house and handed me a floppy (yes, a floppy) with Acrobat 2 on it. He was really excited about PDFs and wanted me to try it right away on a real typesetting job. The best part was that Adobe was giving version 2 away free (they had tried to charge, like, $50 for version 1, and I ignored it at the time.) I installed it. The guts were in the app called "Exchange."
I took to it like a duck takes to water, stayed with it all the way through to now, learned everything I could, used it on the books I was doing production on in the late 1990s, got rave feedback from the book printers regarding the fact that my PDFs actually ran right on the first try.
Meanwhile, today was slow so I bit the bullet and performed a clean upgrade. I uninstalled Pitstop. This... somehow... also disabled Acrobat Pro. Oh well, onward. Uninstalled Acrobat. Reinstalled Acrobat. Ran the updater. Reinstalled Pitstop. All fixed. And, while I'm sure there's a perfectly rational cybernetic explanation for all this crap, I'm losing my love for Adobe Systems...