The first problem is that it is not a perpetual motion machine: If it does what it says it does, then it would be a machine powered by a source of energy so vast, we could never exhaust it, I.E. gravity from celestial bodies.
The second problem is that this machine is not special. We already have this sort of, "Perpetual motion". It's called the Tides. And you can be damn sure that harnessing tidal power is a hell of a lot more feasible, practical, and larger scale, then this contraption.
Third, it could always just be plain old BS.