Formatting issue with advsearch box

While I've got Adv Search to work, there's a strange formatting issue with the search box. See http://www.markdeangarner.com.au/help/advance-search

In Google Chrome there's just a few punctuation marks in the box and the actual search term appears underneath the field. In Firefox you can only see half the search term.

Any ideas as to what's causing this?

Thanks