When you have the Terminal in the recent applications menu, and Netinfo Manager in the foreground, launch the Terminal (from the Recent Items Apple menu) and you will be logged in as the root user. The person who posted said that he didn't even have the root password enabled.
I tried this (I do have the root password enabled) in 10.1 (5G64) and the same thing happened.
[Editor's addition: The MacNN forums go on to pinpoint the cause (Netinfo Manager essentially runs as root while it's running) as well as a workaround - disable excecute permissions for those who aren't members of the Admin group. However, exactly HOW to do this is not listed. You should be able to do this in the terminal:
sudo chmod o-x "/Applications/Utilities/NetInfo Manager.app/Contents/MacOS/NetInfo Manager"This removes the execute bit for "others", leaving it for "user" (root) and "group" (admin, which your normal user is a part of). I switched mine, and my admin user continues to be able to use NetInfo Manager, but I don't have a non-admin user to test with at the moment.]
[NOTE: Above recommendation reflects comments listed below - thanks all!]

