Despite the fact that its pref pane has been working correctly (Finally!) I still check my Flash prefs periodically, and tonight I discovered that my three "blocks" had reverted to "allows".
I reset them, and a short while later they reverted again, so I reset them, and....
I think I check my prefs often enough to safely say that this behavior is associated with the most recent version of Flash, v 11.9.900.170.
For the moment, I've disabled Flash, and I advise everybody to check their own prefs.
Update: With Flash disabled I was able to d/l and reinstall, but no joy.
