Same old story - need to stretch the "menu" div to the same depth as the "content" div (or 100% height of "wrapper" div)...

<html>

<head>
<style type="text/css" media="screen"><!--

#wrapper { height: auto }
#menu { visibility: visible; position: absolute; top: 155px; left: -1px; width: 140px; border-top: 1px solid #ccc; border-right: 1px solid #ccc }
#content { visibility: visible; position: absolute; top: 155px; left: 155px; width: 504px; height: auto; border-top: 1px solid #ddd; border-right: 1px solid #ddd }
--></style>
</head>

<body>
<div id="wrapper">
<div id="menu">
<p><a href="(EmptyReference!)">Menu item #1</a>
<br>
<a href="(EmptyReference!)">Menu item #1</a></p>
</div>
<div id="content">
Text.<br>
Text.<br>
Text.<br>
Text.<br>
Text.<br>
Text.<br>
Text.<br>
Text.<br>
Text.<br>
</div>
</div>
</body>

</html>