Adding an ad to primary sidebar wrecks my page

I've been trying to work out the cause of one of my pages being messed up, finally found it. Whenever I insert the code for an Amazon ad banner into a text widget on the primary sidebar on Wordpress, my footer disappears along with the wp admin bar at the top of the page. If I just use the image code it's fine, but image + text = nope.

Anyone know how to sort this out?

First & last bump

Sounds like a CSS or HTML problem. I'd take this problem over to an HTML or webmaster forum for a better answer. You'll probably have to share your code there as well so have some neutered code ready that doesn't give away your site's info..