Are you talking about the gap in the lip just under each fake airduct? If so, this is pretty common, even with the genuine Amuse product. You must either have it filled in (moulded) or just live with it as most people do. If you are talking about where the lip wraps around the fender and into the wheel well, this part might need to be sanded down or Dremelled to fit properly.
When you say you have no screws, are you meaning you don't have ANY bolts or other metal fasteners either? If so, this is not the way it was meant to be. As per my "How To", you need to have bolts and cylinders of different lengths (4 sets in total) to attach the lip to the underside of your front bumper.