Can't run Software Update since upgrade

[Alan Evans]

I was a F13 holdout for a long time and finally caved to my machine
constantly nagging me to upgrade. I did the upgrade (preupgrade) to
F14, since I'm not ready to endure all the changes in F15. Still, I'm
surprised at the number of things that subtly (and not-so-subtly)
broke. I'll take it one thing at at time...

Today, the little icon in the system tray tells me that there are
updates, and clicking on it sure enough brings up the "Software
Update" app. However, selecting "Install Updates" merely results in a
dialog:

   Authorization failed
   You have failed to provide correct authorization.
   Please check any passwords or account settings.

I was never asked to provide a password. Clicking on the "More
details" dropdown, helpfully states:

   Failed to obtain authentication.

Gee, thanks for the additional details!

This same thing happened yesterday and I found that I could do the
update from a terminal with yum update. So I guess this isn't an
absolute show-stopper, but the GUI app ought to work, I think. How
should I begin troubleshooting this (like where should I go to
*actually* get more details)?

-Alan