It's difficult to say since all we can see is the HTML output that your PHP file(s) produce.
First port of call would be to remove the Flash code - a glance at the page source reveals that you are referencing a very old version of Flash, and it's a non-standard loader script that mdoern versions of IE can't cope with.
I saved a local copy of your page, removed all of the Flash <object> code and it rendered all other content in Internet Explorer.
That should give you a bare-bones, PHP-produced-html-only view with no eye-candy to speak of.
Since you are using Project PVII it is a fair assumption that you are using Dreamweaver as your editor of choice. Dreamweaver versions after MX all have various browser testing and code checking tools built in, and you get more of them the more current your version of Dreamweaver.
You might want to invest some time in running those built-in checks, which should allow you to get to the bottom of some or even all of your page problems in short order.
Can't offer anything else until the coffee kicks in, but that Flash <object> code stinks...