In the header.php page, there is this line of code (in case you hadn't seen this yet):
<div id="top">
[img]<?php bloginfo('template_url'); ?>/images/top.gif[/img]
</div>
This is what controls the image that appears at the top, which is the "black to gray" gradient. If you remove this portion of the code, you will not see this image anymore.
You said you already fixed it, so maybe you won't need this post! :)