<p>The list of supported browsers is <a href="http://meta.stackexchange.com/questions/56161/which-browsers-are-officially-supported-and-what-else-do-i-need">over on mSO</a>. Your Firefox 3.6 is listed as</p>

<ul>
<li>Firefox 4 (and earlier) — probably unsupported (old version).</li>
</ul>