Originally posted by Dave Clark
I have never seen a target that is able to find a named frame that is not in the same browser window.
Take a peak at this code then for a new experience 
Index.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title></title>
</head>
<frameset border="0"> <!-- border="0" is a bugfix for IE, NS as well as Opera -->
<frame name="main" src="initial.html" frameborder="0" marginwidth="1" marginheight="1" scrolling="auto" />
<noframes>
<body>
<p>
Frames are not working in your Browser.<br />
If you have Frames turned off, please turn it on to view this site.
</p>
</body>
</noframes>
</frameset>
</html>
initial.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<meta http-equiv="Content-Script-Type" content="text/javascript" />
<meta http-equiv="Content-Style-Type" content="text/css" />
<title></title>
</head>
<body>
<p>
<a target="blank" href="blank.html">open blank</a>
</p>
</body>
</html>
blank.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<meta http-equiv="Content-Script-Type" content="text/javascript" />
<meta http-equiv="Content-Style-Type" content="text/css" />
<title></title>
<link rel="stylesheet" title="Default" media="screen" href="main.css" type="text/css" />
</head>
<body>
<p>
<a target="main" href="blank.html">open in main</a>
</p>
</body>
</html>