Default page will not load unless put a double slash at the end

I have set up IIS 6 to work with multiple sites. On some sites I can access the default page (index.php or index.html) by just typing in the domain name. However, with my-study-club.com, I cannot access the default HTML page by typing the domain. I have set up the load default page function, but it still wouldn't work. Help please~~

re: Default page will not load unless put a double slash at the end

What is your OS? I believe that there restrictions to the number of domains you can host on a machine, especially xp.