Did you change the password at Google and forget to do it in iChat ?
Is Talk still Enabled at your Google Account Settings ?
In re-adding the account you ar using the "right" ending (@gmail.com or @googlemail.com) ?
Try deleting com.apple.ichat.Jabber.com
You will need to do this in the Finder
Use the Go Menu.
Hold th ALT key and select th Library
Find the .plist and Drag to Trash
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