copying jquery files into misc stops node creation

Hi,

I have installed the jquery update module for Feedback 2.0. In doing this I cannot post new nodes or edit old nodes... the browser simply has a blank page (and an enable richtext for tinymce in the top left corner). removing the files and restoring the originals allows it to work again but the feedback module then has presentation glitches. The site is at www.plusgroups.org.uk

Thanks for your time

Rich