Insert Image doesn’t work

Whenever I try to insert image and press show link. It says Webpage Script Errors

User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; FDM)
Timestamp: Mon, 27 Oct 2008 22:38:34 UTC

Message: Object doesn’t support this property or method
Line: 52
Char: 37
Code: 0
URI: http://paknewz.com/wp-admin/media-upload.php?post_id=470&type=image&tab=library

Plz help me. I really need to fix this error. I delete file from wp-content upgrade folder. Also upgrade to 2.6.3.