SecurityAgent Logon Error - 10.7.5 update

Question

Seeing this issue (again) after updating from 10.7.4 to 10.7.5 on MacBook Pro.
It occurs when a non-admin AD user attempts to login over PEAP wireless (WPA2 Enterprise).
The error is:
"SecurityAgent wants to make changes. Type an administrator's name and password to allow this."
This is a client, and not a server issue, but it may only affect enterprise setups, so I believe that is how the issue was filed here.
The issue is resolved by downgrading the MacBook Pro to 10.7.4.

Answer 1

After an hour, I tried to quit iCalendar. It was "application not responding," so I force quit, and got back in. In the title bar, it said it was updating, for maybe 45 seconds. Now it's fine and my historical data (stored locally) is there.
I upgraded another machine, and the Updating progress dialog box appeared for less than a minute and then was fine.
There's probably something underlying that's wrong with my main machine. Guess I'd better get on with cleaning up.