sidebar missing in IE 6, reappears after reloading several times

The sidebar in the theme I’m working on seems fine in Safari, and Firefox, but dissapears in IE for PC. I have put in a separate set of IE only styles in the header. If I go to the page and reload it a couple of times, it shows up some of the time. I have validated the XHTML and CSS and I’m stumped. I’ve adjusted the widths in the IE stuff so that I think it should fit. (In the process I’ve added some background colors to the IE stuff just so I could see it.) Now, I always thought that generally a computer would react the same way to the same conditions, so I don’t understand the random way the sidebar appears when I reload the page, but only sometimes. Here’s the page
salzerdesign.com/wordpress
Help would be very very much appreciated!!