Is this the first time programming this homelink? I doubt that <- but you could reset the thing by pushing and holding the outer two buttons until the LED begins to flash. Then try the programming steps. Just make sure you hold the buttons long enough to get the rapid flashing (20 - 30 seconds i think)

__________________
Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE