Sounds like your remote reverted to an earlier technology. This is what causes this kind of problem. Go to Sears and get a new remote with the same model number you listed. You should then be able to program it and your keypad.

maybe you are using a earlier fixed-code technology which uses dip switches to set the address pins of encoder and decoder ic, when you do the programming, maybe you should check your manual for dip switch addressing information.
and maybe you should check out the garage door opener remote dip switch calculator at solidremote, it will save you a lot of calculations.

Here is a link that might be useful: garage door opener remote dip switch calculator