Exposure button not working

This maybe a repeat message before I signed up for premium advise service. I have a Nikon D200 ( for a couple of year) While shooting a football game I filled up my memory card so I changed it with another 4 gig Ultra SanDisk memory card. Suddenly I could no longer shoot exposures. and if I tried to look at the card the screen read "This card cannot be used" and there were the letters CHA flashing on the control panel. I tried formatting the card, which worked, but the problem was still there. I changed the card again, and again, and again. I replaced the battery twice. I reverted custom setting back to factory defaults and then checked every button, knob and lever to be sure there wasn't anything "between" settings. I also changed lens twice. I have about 8 scandisk cards, all 1, 2, or 4 gig. I've been using these for years. They were all empty and ready to use. I have five Nikon batteries for the D200 and they are all charged and read full when you put the battery in the camers. I could find any listing in the manual for these letters (CHA) or for this problem.