Iframe in Site Description

Hello,
I want to embed some nav buttons in my header so my forum looks like the rest of my site. Using the technique suggested for embedding a flash header, I instead used an Iframe in the site description field. The Iframe works great, but the whole rest of the forum beneath it disappears! Any ideas? Here's the code I used:

<iframe src='http://www.cryptozoic.com/CZE-forum.htm' frameborder='0' height='86' width='808' scrolling='no'></frame>