If the door starts to close and then reverses and the main light flashes 10 times it is a door sensor problem. Make sure the small light on each sensor is lit and not blinking ever so slightly. Try tweaking them a bit to see if the problem improves. If not call Sears and let them figure it out. There is a warranty.

Thank you very much for the idea. The sensor lights always glowed, never flickered or went out, so I assumed they were aligned correctly. Your recommendation to tweak them worked. I moved the sending unit ever so slightly and the door opener is working fine. The sensor never did flicker or go out the entire time I re-aligned it.
Thanks again,