I doubt anyones going to be able to read through your code, it's pretty bad. I mean, look at this:

<div id='dm_1' class='dm' style='right:20px;'> <table id='dmt_1'> <tr><td class='dms'></td></tr><tr><td class='dmi' onmouseover='omega.doHover("1","dm","dm");' onmouseout='omega.undoHover("1","dm","dm")'> <a href='/arcade' onclick='return false;' title='Go to the Forum Arcade'><span id='en-gb_arcade'> Arcade </span></a> </td></tr> </table> </div>

... and that's just for ONE navigation link! :O

I would recommend you look at some of the navigation techniques on listamatic. Most of them work around IE6's crappy support of the :hover selector aswell as some of it's other quirks so they should work fine cross browser.

and organising anything like that with Divs is impossible for any browser other than Internet Explorer

Your probably just not compensating for IE's incorrect implementation of the box model. It's pretty easy to work around. (there are details on that page)

As for the content not displaying in IE, I believe it is something to do with your javascript, you should probably try to debug it a bit. (I'm a bit busy to do that atm)