XAMPP path settings

[eluser]Unknown[/eluser]
I have XAMPP running on a separate drive F: I have defined my windows xp host file to read
127.0.0.1 CIDemo.com localhost.

When I browse to http://cidemo.com the system launches the xamp index.php file because that is what is defined to happen in /htdocs/index.php. However, if I change the index.php file to read header('Location: '.$uri.'/CodeIgniter/'); I get a file not found error, unless I put CodeIgniter under /xampp/htdocs/.

My httpd.conf file shows ServerRoot "F:/xampp/apache". It shows DocumentRoot "F:/xampp/htdocs". Does that mean the folder located at F:\CodeIgniter\index.php is really seen by the apache server as F:/xampp/apache/xampp/htdocs/CodeIgniter/index.php?

If so, how does the system parse http://cidemo.com/Codeigniter/index.php?
What changes would I need to make to get the line above to launch?

If I make changes in httpd.conf file for DocumentRoot, will that cause the other utilities such as PHPMyAdmin grief?

Thanks.