Hi,
A Google Account on Messages uses port 5223 (using SSL ) to Login.
The Visible Invite the Buddy sees is sent on Port 5678 (it arrives at his end and if he replies that is notes back to your end on port 5678)
At the same time as he accepts the SIP process starts (Session Initiation Protocol)
This send another Invite (behind the Scenes ) and it is this one that the Window is Waiting for the Response to.
This behind the scenes invite is on port 16402 as first choice.
If the SIP complete the connection the A/V chat is also on port 16402 in version 4 or iChat and higher.
Things that could have changed since you used iChat 6
The Upgrade may mean that Messages is not allowed in the Mac Firewall (System Preference >Security & Privacy > Firewall > Unlock then Firewall Options)
Messages should be in the List if th Firewall Is ON
Also If On the Allow Signed Software should be enabled.
The Stealth option should not be ON.
Next check your router.
(this seems less likely as you can Video Chat between two Computers behind the router.
Check it is doing UPnP
Make sure it is not blocking the IP your friend's computer has been given.
His ID
It should be a Google MaIl ID (No other Google ID will do.)
He needs to have Enabled Talk on his Google Account settings.
He needs to double chech the name he is using. The Mail App seems to allow you to "switch" between @gmail.com and @googelmail.com but iChat and Messages (or rather the GoogleTalk server) is more fussy about this.
7:53 PM Monday; August 13, 2012
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Lion 10.7.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images." No, Seriously