Why do my replacement light bulbs not function?
Are these driveway lights controlled by a day/night control of some kind? If so, an incandescent control needs only 2 wires to operate but CFL's or LED's need a different 3 wire control. Try screwing in another incandescent bulb to see if that fixture still works.  If it does, and you have a day night control you will need to get the correct control. If you have a descent volt meter and know how to use it properly and safely you could check to see if you have voltage at the socket. If that light socket is old, it could have broken when you removed the first light bulb. One last thing, sometimes, when you buy a replacement bulb, if they are a cheap foreign brand, their quality control is poor and the bulbs contacts are not exactly as they should be.