Topic: scrolling divs expand on click?

hey, i just tested my site in NS6 and whenever you click on a div scrollbar the cell expands to the right... any clue whats causing this? http://charmed.numbaa1.co.uk/main.php is the site, I just downloaded NS6 so im not really used to it and have nc what is going on...anyways thanx in advance for any help cya