Problem with Nikon D80?

I haven't used my camera for a while so i took it out today. It's acting weird. For example, when i take off the lens, it still shutters?
and there's an "err" with it.
when i press the button to take a picture, it shutters, but takes no picture.
there's nothing wrong with the sd card, or battery.

What do you mean by shutter?
What lens are you using?