Last week my 722 was programmed to record 3 shows in a row on the same channel. It recorded all shows normally.... or at least, when I reviewed the recorded-show screen, all showed up with their program length normally. Later, we watched the first two shows. When I opened the 3rd show, the screen displayed a box which said Error 4. I tried repeatedly to play the program, but it would not play. Anybody got an idea what may have caused an Error 4? I did not notice any power failure, or other issue. It took me a while to figure out how to delete it from the recorded show directory.