media uploader problem

I have a problem when using IE8 and trying to add an image to a post.
On clicking the upload/insert link, up pops an error:

Message: Syntax error, unrecognized expression: [class^=delete:categorychecklist:]
Line: 3
Char: 14659
Code: 0
URI: http://example.com/wp-admin/load-scripts.php?c=0&load=jquery,utils&ver=edec3fab0cb6297ea474806db1895fa7

It works fine on Firefox and Safari.. well it shows an error but it doesnt stop it working!

Ive had a look on google and it seems to be a jquery problem, but I’m a newbie to WordPress and cant see how to chase down the exact file thats causing the error?

Any pointers would be greatly appreciated, thanks

Jim