I learned tonight that Compact Flash cards have a finite life. All of a sudden my camera stopped working and this turned out to be the culprit. I'd use the card from Christmas last year and had success with it through Halloween, but I've taken a TON of photos in that time, and I feel it has led a productive life. The good news is that its successor has double the memory, which means double the photos I can take at a time! RIP old camera card!