IChat worked great under 10.4.6, has not worked since 10.4.7

Question

We use IChat to video conference between offices(in different cities.) We have VPN and our connectivity at both ends is T3 supplied by the same vendor. We have a server which supplies DHCP to the network.
Before 10.4.7 it all worked great, simple and easy. Since the update we can see each other, text each other and invite each other to video chats, but every time the invitation hangs with the "error -8" so many people are complaining about.
I checked the forums for things to do.
Checked for any ports blocked at the ISP end, Tried port 443 instead of 1080, tried with Firewall on or off etc etc. Thus far nothing has worked and I have spent SO much time on this with no result.
It all leads me to these questions:
1. why am I forced to spend so much time trying to make this work, when it was working fine before and the only change we made was updating OSX to 10.4.7?
2. How can Apple expect people to have to change things like port settings on a product which was widely touted as simple to use?
3. How could we have gone through several updates since 10.4.7 without this clearly widespread issue not being resolved?
I am a lifetime mac user, and though there have been occasional let downs, I am a generally a very happy mac user.
I must say I have never been left out to dry like this. I advised my company to use Ichat for video coferencing, and now I have egg on my face, and Apple does not seem to be even taking responsibility for this.
whats going on? can anyone please help me?
G5 dual 2Ghz Mac OS X (10.4.8) T3
G5 dual 2Ghz Mac OS X (10.4.8) T3
G5 dual 2Ghz   Mac OS X (10.4.8)   T3

Answer 1

Sometimes when expiriencing trouble after an update this is a way that often fixes these issues:
Common workarounds after system updates.
Apply the Mac OS X 10.4.8 combo updater Once again, re-application of the current combination updater (Mac OS X 10.4.8 for PowerPC or Intel) has proven useful in the case of Security Update 2006-008. Doing so overwrites potentially problem-causing files.
Apply the Mac OS X 10.4.8 combo updater from an alternate startup volume Failing the above, a more involved process that requires applying the combo updater from a separate startup drive can clear various issues.
JP