I don't know what to say. I am due to install Windows XP under a virtual machine so I can do this exact kind of thing - test webpages on a computer that is not up to date. I can't downgrade from Internet Explorer 8 to version 7, nor would I want to...
IE8 works fine though. When I change to compatibility view, the comment still posted but I got the following error still:
Webpage error details
User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; FDM; InfoPath.2; eMusic DLM/4)
Timestamp: Wed, 15 Jul 2009 09:27:28 UTC
Message: 'getElementsByTagName(...).0' is null or not an object
Line: 859
Char: 5
Code: 0
URI: http://weigelfuneralmandan.com/components/com_comment/joscomment/jscripts/client.js
You could always do what everyone should be doing - check the User Agent and if it's IE7 make a modal popup appear and tell them to use a browser that isn't crappy
But yeah, that hurts potential audiences...
I wish Google blocked IE7 to be honest