Hi Joe,
You're on the right track but your html is a little malformed. When I view the source of your page I see this:
<a href="~/NHTAHome.aspx"> <div class="art-logo">
<a href='#startcontent' class='skiplink'>Skip over navigation</a>
<div id="ctl01_InsecurePanel1" class="addthisbutton" </div>
</div></a>
I would try changing it like this:
<a href="/NHTAHome.aspx"><div class="art-logo"></div></a>
<a href='#startcontent' class='skiplink'>Skip over navigation</a>
<div id="ctl01_InsecurePanel1" class="addthisbutton" </div>
ie move the closing div and link from the bottom so that the skiplink and the insecure panel is not inside the art-logo div and get rid of the ~ in the link
Nice site!
Hope that helps,
Joe