Take a look at this page:
Features and Operation of the Ka Mount
The contacts on your lens give the camera a binary code to signify what the lens' aperture range is. Each contact is one digit: a plastic (insulated) contact is a 0, and a metal (conductive) contact is a 1.
The code your lens is supposed to make is 0
11*10, where the * is the contact that tells the camera it's an auto-aperture lens. That code means f/2.8-f/22. The code your camera is getting is 0
01*10, which means f/4-f/22. The metal contact which is second from the bottom is not making contact, so the camera thinks it's an insulator, or a 0. It's either dirty or too far recessed to make contact. If cleaning it (use rubbing alcohol and a cloth) doesn't work, try putting a little piece of metal foil over it.