[Michael P]

I'd look closer at your stylesheets:

background: #D5D8E5 url(../../images/gradients/gradient_panelsurround.gif) repeat-x top left;
color: #000000;

these kinds of relative URLs are likely to get you in trouble when using files outside the normal directory structure. I'd change them to absolute paths like:

background: #D5D8E5 url(/forum/images/gradients/gradient_panelsurround.gif) repeat-x top left;
color: #000000;

You can see the vB3 mapping of style variables at the bottom of the forums/vb3.php file.