Rendering problems with IE 7

I am hacing some serious rendering problems with IE7 (all of the other browsers display ok). The post box is loading all the way to the bottom of the page… It seems it is too wide to hold in the middle of the page… the sidebar is OK… I am trying to figure out the correct CSS for that box but I can’t figure it out. Does anyone know what is the style of that box and what would be the best width for IE 7 to make it fit into the theme without affecting other browsers…