Shared Folder not showing up, no option in preferences to "look for shared libraries"

I have followed all of the instructions to set up sharing of my iTunes library with my daughters' computers and am unable to get it to work. The Shared folder is not present in iTunes and in the preferences menu, it says that sharing is on but no computers are connected. Is this a problem with an iTunes update? My sharing has worked in the past, but hasn't worked since the latest update!