I need help...

I've decided to test "My Living Desktop" in the second Lion's preview and, for my surprise, it is running. But when I try to register it says that I can register only as Administrator ( well, I am the administrator...at least I think I am... ). The pop up says that I have to log off and log on as administrator...How can I do that?...I mean How can I install a software that says that I can run it only if I am the administrator?...