Hi Ronald, thank you for also answering. I'll try to answer your questions in order.
Yes, I am using SS 2.3 (25 Oct 2009 version).
I deleted the invisible prefs file and set up SS again. I deleted the file manually and also tried using the script. Both times it deleted, but no help with the networking. I also zapped the PRAM just for good measure.
I confirmed the slirp setting. I get the correct IP address in the TCP/IP Control Panel.
The network at my work assigns "10 Series" IP addresses (i.e. IP=10.1.1.10, subnet=255.0.0.0, router=10.0.0.63)
My router at home assigns "192 Series" IP addresses (i.e. IP=192.168.1.116, subnet=255,255,255,0, router=192.168.1.1)
I tried with the Mac OS X firewall off and on (it's usually on).
Lastly - and this is strange - I can successfully hit the router's "home page" by entering 192.168.1.1 into a browser address bar. So it appears that I can connect as far as the router, and I was also able to access another PPC machine running 8.6 using AppleShare in Chooser and selecting Server IP Address, then manually typing in the address of the 8.6 machine. But still no access to the Internet. In contrast, when I copied the same SS folder over to my PPC PowerBook (Tiger) everything worked fine upon booting without any changes.
Normally, I would exclude the router as the problem since SS on the PPC PowerBook can get on the internet, but just to be sure, I disabled the WEP encryption temporarily to see if that helped but it made no difference. SS on my Intel MacBookPro still cannot get on the internet.
Lastly, when I try to access www.google.com
(or any other site) in iCab the error message I get is "Server "www.google.com" is currently inaccessible. (Network Error #-3264)"
Any ideas? I'm stumped, and I've been using networked Macs for over 20 years!
P.S. Do Appletalk settings matter?