Nikon D90X flashing Err, P and metering system?

Just recently the problem suddenly occurred and my camera started flashing Err. If I change it to manual mode 'M' the M does no flash like the P does, same with the metering system, but no matter what I try the shutter speed, it never reverses. One more thing, I've already read the manual, pressed the green reset buttons, taken out the batteries and taken out the lens? Any other options?

Added (1). I'm sorry I meant the F90X

There's a trouble shooting section on the user manual.

Look on page 256 and you will see that Err is telling you to contact your authorized Nikon service representative.

You may want to call Nikon.

Nikon's helpline in the States. 800. NIKON-UX

Page 143 of the user manual it means that a Non-DX-coded film or film with unacceptable DX code is loaded. Set manually to correct setting. Page 100 on how to set ISO manually.