The edit below is a fix for IE7 as you have so many stylesheets and codes that I haven't got the time to find the real source of the problem.
Add this just before the </head> closing tag, after the stylesheet links:-
<!--[if IE]>
<style type="text/css">
#menulist_root-suckerfish-vertical { margin-left: -115px; padding-left: 0; }
</style>
<![endif]-->
which drags the menu to the left only in all IE browsers. I didn't check IE6 but if IE6 is wrong you can set different conditional comments for each IE version like <!--[if IE 7]> for IE7 and <!--[if lt IE 7]> for all less than IE7 (note the space between IE and 7).
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.