I have NIS 2009 running on Windows XP Home SP 3.
In my Administrator account, I can right-click on any file and see the Norton Internet Security context menu item (Scan Now). However, this context menu item is missing in Limited accounts. My Limited users see only a blank space on the context menu, and clicking on the blank space does not produce an on-demand scan.
I also noticed that, while Norton Internet Security appears in my Limited users' Start menus, none of the selections are clickable. (That is, you click on them and nothing happens.) I presumed that this was intentional, since you don't want Limited users to mess with the program settings. But perhaps this is related to the problem described above?