Hi George! I've been checking around. The Teredo Tunneling is an interface with IPv4, and comes with Vista by default. Removing it shouldn't break anything. But then again, having it there shouldn't break anything either. (I read somewhere that people with "Utorrent" or P2P get that flag and it can be safely be ignored. but that was awhile ago and I'm not sure if I got my facts straight-- ) If you want to system restore you can try going to properties of your network connection and uncheck IPv6 and go with only IPv4. I'm not sure if that will fix the flagging but you can try.
(Teredo tunneling is a method of tunneling IPv6 over a IPv4 network). It is best to make your network 100% IPv6 or 100% IPv4. Most home users are stuck with IPv4 because their routers and switches can't handle IPv6.