Supporters - Statistics

When viewing the statistics on the supporter homepage I am getting the following error on IE 7 and 8.

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; InfoPath.2)
Timestamp: Mon, 14 Dec 2009 20:56:49 UTC

Message: 'parentNode' is null or not an object
Line: 1
Char: 1026
Code: 0
URI: http://weblog.com/wp-content/mu-plugins/supporter-files/js/excanvas.pack.js?ver=2.8.6

Any ideas?