Facebook doesn’t allow people to track who views their profiles. Facebook applications, on the other hand, are unable to track anybody unless they have the consent of the viewer.

Follow the source to see the Facebook’s statement about this issue.

and the question is..?

they have not, nor will they every work. those applications violate facebook’s terms of service.

I assume that the question is "Who viewed my account on Facebook?"

That "viewer" application doesn’t work because Facebook admin "disables" it. He doesn’t want people to invade another people’s privacy.