The best thing to do is upload the cmp_index.php to your forums folder. That way you will not have as many broken image links on your portal page, also if you make your board private the link from the portal page will take you to the correct login login page without errors like it does if placed in your root directory.
Did you include the server path in your cmp_index file like it asked you to enter. Just follow the instuctions step by stem slow. But upload both the cms_config and the cms_index file to your forums folder instead. And just use a index file in your root folder created to point to the either the portal file or the forum file using this code.
Code:
<META HTTP-EQUIV="Refresh"
CONTENT="0; URL=http://www.yourwebsite.com/forum/index.php">