URL rewriting on a subdomain

[eluser]njr[/eluser]
Hi, I'm having a problem with my URL rewriting on a subdomain, I'm trying to access a private file in my cgi-bin folder. I've used the example exactly as it's done in this wiki: http://codeigniter.com/wiki/mod_rewrite/

But here's the problem: I've noticed that only works if I'm using it on a regular domain, such as http://www.somedomain.com. If I use that same .htaccess file on a domain like http://sub.somedomain.com, my URL rewriting works but now I can't access the contents of my cgi-bin folder. I was able to tell it's the .htaccess file because if I tried without it, everything would work, but I need the rewriting so it removes "index.php" from my URLs.

On the regular domain, I was able to access http://www.somedomain.com/cgi-bin/private/private.cgi

How can I access http://sub.somedomain.com/cgi-bin/private/private.cgi ? Thanks for the help.