Sentry RMC10 doesnt want to be programmed

I press the code search till the light stays on, I release it and then press the TV, DVD, etc. button to program the device. the manual says that the light will blink once and then go back on steady and that it is ready to have the code entered. However, when I do press the deice button, I do not get the blink of the light and after a while the remote shuts down and I have to start from the top. I have tried pressing the device button quickly and slowly, but nothing makes any difference. Any ideas or does anyone have the web site for the company?