I don't have OS X in front of me, but at first glance, I remember some of the earliest builds of OS X had the same problem when opening the Network Prefs. pane. Since I don't have access, I can't remember if Network and Sharing are separate panels or subsets of each other. You're running the release version of OS X, right?
I'm probably way off, but that's the first thing that popped into my head.