How can i fix r25 error on my nikon d200

SOURCE: nikon d200-manual mode

x250 means flash synch speed is set to 1/250.  Is your speedlight connected or is you on-camera flash up?

SOURCE: Trouble auto focusing

If it's any consolation, I have the same setup and the same problem. I'm now at the point where I'm probably going to have to return the lens as faulty, but there are a few things it could be on yours which you might want to check.

Have you got the D200 set to auto-focus? The selector (on the front of the camera, on the lower left) should be in the S position (as opposed to C or M).

Have you got the lens set to auto-focus? It should be in the M/A position, rather than M.

Have you tried cleaning the contacts? Pop the lens off and give the contacts a clean with the appropriate equipment. Dust on the contacts could be causing a problem.

Failing that, have you tried turning the camera on and off a few times?

I've obviously tried all the above on mine, and now suspect I've got a faulty lens that needs fixing ... which really sucks! Good luck with it, let me know if you get it working.

Dan

SOURCE: nikon 18-200 mm vr lens not auto focusing on my nikon d200

lets start with the basics, try hard reseting it and try again, if that doesnt work then
try upgrading your firmware (if possible on your camera) and if that doesnt work then it may be the lens, but dont forget to spend a few hours trying to find a option for it in the meny

SOURCE: Err, R25 on display

The D200 uses a different way of changing the aperture than on that old lens. Set the switch to 22 and lock it with the little lock just above it. It always has to set like this. Now the D200 will stop complaining.

SOURCE: I have a Nikon D200 and the auto focus isn't

There's a small contact area that has to make the electrical contact between the lens and body in order for the autofocus to work. Check this on the body for any damage or corrosion that may keep the connection from happening. There is also a very small mechanical connection between the two pieces - the D200 has the autofocus motor in the body itself - check for a small shaft that may be blocked or damaged as well.