Stacking Order Issue - z-indexing??

I have the code on this page, just view source: http://levelafter.com/post-microsite/index-testing3.html

The problem: mouseOvering the links in the ul below displays a new box but it draws behind the div's to the left and right of it. I tried z-indexing in CSS, with no luck.

I am still new to jQuery, I was wondering if there was something simple I am overlooking.

Thanks in advance!