This one stumped me too. Finally I called Apple Tech Support.
After installing from disk, the first thing you need to do is install the SECURITY UPDATE from 7-14-02. (I think that's the date) This will enable all of the other updates.
I know that seems odd, but it has to do with the whole downloadable updates security issue that cropped up recently.
One other thing. There are 2 DIFFERENT secutiy updates available for downloading that have the same file name. One is for those who are installing 10.1 the other is for those who have the 10.1.1 disk. Make sure you install the correct one.
Good luck. E-mail me if you have other questions.
