After upgrading, when I make a reply to a Topic, the Confirmation of the post returns me to the Home page rather then returning me to the updated Topic. Any hints what I may have done wrong?
I agree with Podge. It's most likely an over-active firewall of anti-virus program that disallows browsers to show the referer (the page from which you came). This information is vital for many sites as it'll let the new page know where you came from so it'll be able to send you back to it later.
Disabling the software will do the trick, but will also leave you (and your computer) vulnerable. The best option is to disable the over-active "privacy features" while leaving the rest of the software running. You might have to close all browser windows or even restart your computer before these changes will take effect, but it should do the trick. And don't worry; the referer information isn't privacy sensitive unless you're worried site administrators will check where you came from before you went to their sites (who has time to do that?).
Yes, it's absolutely related to the firewall. Disabling Norton Internet Security Firewall fixed the problem. I have both SP2 Security Center and Norton Firewall Security. I'll explore the "allow referer" hint and try to figure out what settings will still allow me to keep a firewall in place but still allow the referer routine to work. I've been favoring Norton... so I'll work with that first.