Thanks, guys! Yes, Eric, I do have a volt meter - I'll pull it out and get you some more numbers...
I think you may have hit the nail on the head about the rope lights, though - although they are nearly brand new, there is about a 4' section that does not light.... oddly enough, there is about 6' of lights beyond these dark bulbs that do light, so juice is getting to them somehow.... could it still possibly be a "short" where they're dark? The ones that are lit beyond the dark bulbs do not appear to be any more dim than the bulbs preceding the "short" - maybe I'll just return them and see if a properly functioning one exhibits the same symptoms...
John, yes, I know the kill-a-watt you're talking about - don't have one, but have frequently thought it would be handy to have. Though, as I said, I do have a pretty good volt meter, so maybe I could garner the same info from that? Not sure, as I said, my electrical knowledge is pretty rudimentary...