Thanks for the 8787 tip. I've taken a few runs at that with Windows 7 Pro + AVG Free 9.0. This seems like such an easy fix; perhaps it can be added to the FAQ as an alternative?
Second point: I have added calibre.exe to have full private / public access through the Windows Firewall AND on my router, allowed HTTP incoming AND port forwarding 8787 to 80.
So far so good -- another computer BEHIND the firewall has access using the 192.168.x.x:8787 and correctly grabs the calibre index. But I still can't figure out how to make a computer on the OUTSIDE of the router see 99.230.x.x:8787 which is the address of the machine running Calibre (according to:
http://www.whatismyip.com/).