I have found a solution/workaround. I made a new Jabber account (instead of Google Talk account) and followed the instructions Google provides here. http://support.google.com/talk/bin/answer.py?hl=en&answer=24076
The main difference seems to be the address of the server is talk.google.com instead of the default that iChat/Messages uses which is gmail.com
So I am back online now with Google Talk using Messages.
Those instructions are for iChat 3 (when they added Jabber as an option but not Google)
Google do not follow the naming convention of other Jabber Servers.
Therefore in iChat 3 the pulled the @gmail.com (or @googlemail.com) from the User ID as the server name.
Google as you have found use a server called "talk.google.com".
Later versions of iChat and the Messages Beta allow for this server naming issue by having the Google Set up option in the Add Account pane.
The port is usually port 5223 with SSL turned On (It does not work without SSL)
It can be changed (whilst logged out) to port 443 which also works.
I am finding it hard to see why something that was set up and working in iChat 6 did not make the cross over to Messages beta correctly. (other than it is a Beta)
Is it possible that this particular Google account set up was an iChat 3 one that has been migrated across computers til now ?
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Lion 10.7.3)
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
Had the same issue. Oddly on one machine but not others, so this must be a glitch with older account settings as Ralph suggests.
Finally, figured out a solution: under Accounts>Server Settings uncheck "Automatically find server and port" then check SSL and change Server name to talk.google.com (keep the port at 5223). Keep warn before sending password insecurely!
Works fine for me now.