Error with editing or registering users

I copied the error and pasted it below.

Webpage error details

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.0.3705; .NET CLR 1.1.4322; Media Center PC 4.0; BOIE8;ENUS)
Timestamp: Sat, 10 Dec 2011 12:40:41 UTC


Message: Could not get the type property. Invalid argument.
Line: 6
Char: 30
Code: 0
URI: www.uhsupply.com/media/system/js/validate.js


Message: Object doesn't support this property or method
Line: 473
Char: 25
Code: 0
URI: www.uhsupply.com/media/system/js/mootools-core.js


Message: 'document.formvalidator' is null or not an object
Line: 134
Char: 3
Code: 0
URI: www.uhsupply.com/administrator/index.php...er&layout=edit&id=52

We have figured this out. The problem is only present when you are using internet explorer. We used firefox and did not have the problem. So the problem is resolved.