It sounds like your D7000 has developed a fault, since you're seeing focus errors and invalid distance information. The first thing to try would be cleaning the row of electrical contacts in the lens mount area, but if that doesn't improve things a trip to service may be in order.

Whatever you may have read elsewhere, there is no general focusing problem affecting the D7000 - so let's concentrate on fixing your camera

Brian
Welsh Nikonian
Check out the Nikonians Team pages