That would seem to have been the problem I've been fighting all along! My ISP's nameservers are at similar IP addresses, and I guess that in all of these late night-bleary-eyed sessions, I've gotten so accustomed to seeing both those address and my own IP address block that they've blended together.
I transposed a digit in my network address at my DNS host (GoDaddy.com), and never caught it, so now I will have to wait until DNS propagates again to see the results, which is just as well, since I wiped the server and started reloading (again) last night.
Thank you very much!! As soon as DNS propagates, I can finally show my face at work!
(Doing the happy dance!)