Jim, I don't have that same model, but I do have a couple of the older Moultries. We found early on that you need to not just delete the pics/videos from the cards but actually format the card. It would probably even be best to put the card in your computer, format it, then put it in the camera and format it again with the camera. Hope that helps.
(To format it on the computer, just right click on the "card" listed in "My Computer", click on "Format", then make sure that "quick format" is NOT checked.)