feisty -> gutsy upgrade failure

[D. R. Evans]

I followed the instruction meticulously:

  1.   Open the Adept Manager by going to KMenu -> System -> Adept Manager
(Manage Packages)

OK.

   2. In Adept, go to Adept -> Manage Repositories

OK.

   3. Enable the "Recommended updates" and "Pre release updates"
repository, close and reload

OK.


   4. If your system is up to date, the upgrade wizard will be offered
after you click "Fetch Updates" via the "Version Upgrade" button, else..
         1. Press the Full Upgrade button
         2. Press the Apply Changes button
         3. Once the packages are installed, exit the Adept Manager (Adept
-> Quit)
         4. Repeat the initial steps (1 - 3)

OK.... I had to do the Full Upgrade/Apply Changes/Quit/Redo steps 1, 2 3.

So now I press "Version Upgrade" and click through a couple of screens, and
then I get:

"Could not verify the integrity of the upgrader application. This program
will now exit".

At least this time the failure occurred sufficiently early that I didn't
end up with an unbootable system. But what could I possibly have done
wrong? I have been keeping this particular system ruthlessly up to date and
clean of any non-supported applications. It's about as vanilla as a system
could possibly be. So how could the upgrade have failed?