Assuming you've added the directory via ftp or filemanager etc.
Make sure you have an index.html or index.php file that will load by default.
Another note is that directories are case sensitive. If you create a directory 'more' it will not be accessible by domain.com/More
Shooting the breeze here just in case. If you wish the entire contents of that directory to displayed if there is no index page, follow the instructions here:
http://help.directadmin.com/item.php?id=22