IE9 Error Google+1

install latest facebook plugin
latest Google +1
On MU 3.1.3 with buddypress on subdomain
Main site classified theme errors
The Google +1 generates an error in IE9 preventing forms being properly handled.
Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; Trident/5.0; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; Tablet PC 2.0; .NET CLR 1.1.4322; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C; BRI/2)
Timestamp: Mon, 20 Jun 2011 00:35:00 UTC

Message: Cannot continue until a pending callback completes.
Line: 16
Char: 107
Code: 0

There are no errors in IE7 or IE8 or Firefox