How do I delete an empty Aperture project?

I am using Aperture 3.4.4 in my office on a fairly new Mac mini at work. Here, I have several empty projects, which I want to delete. Unfortunately, there is no option to delete these project items under the file menu, or under any of the other menus. At home when I use Aperture 3.4.4 on my MacBook Pro and Mac mini, Aperture has a "delete project" item under the File menu, but that same item isn't available on Aperture 3.4.4 in my office Mac. Why? How do I get that "delete project" item to show up on my installation of Aperture in my office? All 3 of my Macs are running Mac OS X 10.8.3 and all have current updates on everything installed, so I am mystified as to why this issue has occurred.