Any resolve on the looping

?
I have upgraded from 1.1.3 to 2.0.1
I have cleared the browser cache. Several times in sheer desperation...
Tried it in IE; loads with page errors. (yellow ! in left hand bottom corner).
Next day, sober. Problem still exists.
Reinstalled the xml file and re-did the template edits just to be sure....
Problem still exists.
Now this could be the butt of the problem, but I hope it isn't. I'm running vb 3.6.8.
fbconnect-1.1.3 worked fine with it as far as I could see.
Now it doesn't want to load that connect button...
EDIT: Error codes from IE:
Code:
Webpage Script Errors
User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727)
Timestamp: Sat, 3 Jan 2009 10:51:53 UTC
Message: 'YAHOO' is undefined
Line: 29
Char: 1
Code: 0
URI: http://uttertalk.com/clientscript/fbconnect.js
URL:
http://uttertalk.com