From the article, you'll see that the camera only works within a single file. That said, I'm not exactly sure what you want the camera on the LAN to do. You can certainly setup a camera and share the file on a LAN, and each user will be able to see it. If you're trying to use the Excel camera to literally see another computer (what exactly are we looking at??) when working on another computer, it's simply can't be done.