You may also need to add an index.html file to your root directory in order to repoint browsers to your "Main" folder. Some hosting providers do not allow DNN installations in the root directory (godaddy used to be this way, i know).
Here is an example for code to put in an index.htm file in your root if redirection is your only problem:
<html>
<head>
<title>Simple Redirect Script</title>
<SCRIPT LANGUAGE="JavaScript">
<!-- begin hiding JavaScript from old browsers
// define redirect function
// to use this script, change redirect2.htm to required destination
function redirect(){
parent.location.href="redirect2.htm"
}
// End hiding JavaScript -->
</SCRIPT>
</head>
<body bgcolor="#FFFFFF">
<h1>Simple Redirect Script</h1>
<p>This script automatically redirects a visitor from one webpage to another ...
provided that they have a Java enabled browser.</p>
<!-- change "redirect2.htm" to required destination -->
<p>If you are not redirected to another page within 15 seconds, then please <a href="redirect2.htm">click
here</a>.</p>
<SCRIPT LANGUAGE="JavaScript">
<!-- Hide script from old browsers
// set timeout to redirect after 10 seconds
setTimeout("redirect()",10000)
//-->
</SCRIPT>
</body>
</html>