That second DIV tag has no closing bracket, and no closing div tag, far as I could tell. At least when I went to view source.
<div id="middlecontent">
<div
<form action="/index.php" method="get">
<input type="hidden" name="s" value="search" />
<fieldset id="search">
<legend>Search</legend>
<label for="query">Search</label><br />
<input id="query" name="q" size="22" type="text" value="" />
<button type="submit">Search!</button>
</fieldset>
</form>
</div>