Thank you.
What happened after I typed in that boolprop command was rather interesting. Moving the driveway enabled the car to show up but no one got out and I still had the stupid driveway error message. So I added another driveway in the original spot, and my character drives up in a different colored version of the same car and gets out.
The problem seems to be solved, but that was just too weird. Needless to say, I learned my lesson. No cars or driveways on vacation. Walking's healthier anyway.