Canon rebel xti says cf

Check with a magnifier and a flashlight the conditions of the CF memory reader pins. Usually this kind of cameras have the common problem of have bent or broken the CF reader pins. This may caused the original CF error. If you tried to format a CF memory card, then the bent or broken pins may caused the Error 99. By the way, error 99 is applicable to a very open range of problems (lens contacts, faulty shutter, CF memory card access errors, etc). If is under warranty your camera, once you confirm the reason of the problem, send it to Canon for repair. If is out of warranty, you need somebody to repair it, which is not easy for the common person. If need help on repairing it, please contact the ID user Great_items_2004 at ebay. Regards and good luck.