I just fixed this in Acrobat 6, and assume the problem is the same for this thread. First off, my situation: I installed Adobe CS as local admin user, but it is being run by non-admin users. They always got prompted for admin rights in order to open Acrobat.

The fix is to make everything in Microsoft Office's Startup folder writeable by all users. In Terminal (as an admin user), run this command, using the path to your MS Office:

sudo chmod -R a+w /Applications/Microsoft\ Office\ 2004/Office/Startup

Acrobat tries to stick its MS Office toolbars in there every time it starts. I replaced the toolbar files with folders of the same name, in order to disable the toolbars. (The toolbars always go to an inconvenient place on screen, and my users hate them.)

So Acrobat was seeing those files were owned by admin and would not even attempt to overwrite them until the user entered admin credentials.