From testing on http://d-theme.com/fblike. Cynthia Says the theme is US 508 compliant. TV spots the following US 508 error, a heading within a link.

<div id="header_logo">
<a href="/">
<h1>D theme for da Web</h1>
</a>
</div>

TV reported an additional WAI error. The following line is an improperly nested heading.
<h3>User login</h3>