Hey there! I'm so glad for sites like these! Well, the point is, I got a FEE error on my NIKON D80 after putting on an old NIKON 28-85mm AF macro lens. Actually on aperture F22 it's working correctly, but when changing aperture to anything but F22, the error report appears and the camera stopps shooting. What's the matter with that thing?

The Sigma 70-210 f 1:4,5 is an old model, most likely only to be used in manuals focus mode on your Nikon D5x00 camera.
It also needs to be a Nikon version.
Only the Nikon camera's with the LCD screens on top to the right, like D80, D90, D7x00, D300 and above have a focus motor build in, so old AF lenses can be used in AF modes.

Turn the aperture ring on the lens to its smallest setting (largest f/number). You can control the aperture from the camera body, the same way as on a lens without an aperture ring.

try another lens, if work fine, that lens should be broken.

The r11 is in the lower right of the top LCD or view finder that is in the D80 manual page 36 it speaks about the buffer. The r with a number is how many shots the buffer at that moment can handle. It is not an error message. For auto focus issue is the lens in AF as well as the camera?

Check to make sure that the tab is depressing tab on the left-hand side of the mount, when lens is facing you. Also check the contacts and clean them.

Press the AF button on the top of the camera (to the right of the window) to select an AF mode & make sure the M/A (Manual / Auto focus) switch on the lens set to "A"

More info below:

http://www.kenrockwell.com/nikon/d80/af-settings.htm

Switch to M (manual) mode.

To solve this all you need to do is turn the lens' aperture ring (the one nearest the camera body) to the smallest number (probably 22 or 32).

The lens ought to be fully functional in every mode. But if you are in a pinch then Manual it is 'til you can get it sorted or serviced if need be...in which case you'll need to swithch the AF Mode lever (under lens release button )from 'AF' to 'M'. Have you cleaned the lens' electrical contacts? Examine but probably little need to clean the camera's electric contacts considering its' young age. Do you have access to another AF body on which you can test the lens and another AF lens to test the D80?
Please keep in mind that if the aperture is not set (locked) at its minimum, the error is a flashing fEE. When the body cannot communicate with the CPU in the lens, the error is F--, which means either the lens has no CPU or a bad electronic contact.

release the lens at smallest aperture then reattach....