“Suite Product Activation Needed” (Acrobat Pro 9.5.0)

Like several people have on this forum, I upgraded to Lion a few weeks ago with no issues, but trying to launch Acrobat Pro today resulted in this:

I've searched the forii, tried several possible solutions, and all have met with failure so far. I'm running OS X 10.7.3, and the CS5 suite; the version of Acrobat Pro is ostensibly 9.5.0. Is there anything else I can provide that would help turn this around quickly?

—Ken

(P.S. Excuse the screen name. It wasn't accepting my usual one, nor a formal name, and that's what I chose in exasperation—which, of course, it took and now won't let me change.)