If I'm reading your diagram right, and if the 930 suspension is like the Carrera, that's the eccentric bolt on the springplate. Hmmm ... Check out the tech article:
http://www.pelicanparts.com/techarticles/911_suspension_bushings/911_suspension_bushings.htm on the topic, perhaps?
Going fore to aft on the spring plate, the first big bolt (24mm front and back) is the fulcrum about which the spring plate rotates. The second (24mm front, 36mm back) is the eccentric ride height adjustment nut. The two closer to the wheel are for toe-in and camber (iirc, I never touch them). If the 24/36mm nut has come loose, your ride height will be ... random, at best.
To solve this problem, you'll need to go through the ride height routine as Ronin points to above. You also have the interesting complication of probably having pulled that silly bolt out of place. I loosened that particular 24mm nut too far once and discovered that the eccentric bolt will only go in correctly in one spot.
Good luck, let us know what you do with it.
Dan