I use a Nikon D200

I use a Nikon D200 in my photo studio. In the past week, my issue has occured twice, both times very intermitently. I'm in the middle of a session, all it going well and camera is functinoing properly, and is also triggering my strobe lights as it's supposed to. But for some reason unknown to me, the camera will suddently quit recording the images to the disc. It is still functioning as though it is, but I cannot see the images on the LCD screen and there is no record of them on the disc. I switch the disc out, and the camera functions properly. After the session, I switch back to the original disc that was in when the situation first occurred. Images record just fine. Originally thought it was disc error, but I got rid of the disc from the first instance. It has now happened again. Can you help?