Originally Posted by g-kun
Thanks for the idea. I checked contacts and cleaned them with cloth. I also checked the aperture acturator lever. When there is no lens mounted, it sticks out in about half of its hole. When I release the shutter, slides up and back slightly. When I mount the lens, it doesn't work.
The error you faced and described is simply that you body no longer recognises Auto aperture lenses.
You body detects Auto lenses by electrical contacts. So, try to use a soft towel which is slightly wet with water to rub the contacts of your body and let them dry out before you re-attach your lenses. Do try more than one lens as it might be your lens!
To check the proper functioning of the aperture actuator, put your body in M mode and push the green or AE-L button and to see if it will close down your lenses to stopped down (in case of DA or and Auto lenses, the smallest aperture will be closed).
If problem still persist, pull battery out of your body and let the camera forget all its memory and then re-insert it. I guess one or two days may be needed. If the camera ask you to enter the date/time and clock again, you succeed! Otherwise, re-try! :-)
Good luck and I hope you can resolve the problem by yourself!