directory listing instead of web page

Hello,
I've got a strange one here. I've got apache 2.0.49 running on a FreeBSD
5.2.1 box. User's put files on the webserver via samba mapped network drives
so they can do there development under windows, which is where most of them
are comfortable with. I've got a file index.html in the root of my
DocumentRoot which is /usr/local/www/data. My directoryIndex variable is set
to index.html index.php and httpd -S and httpd -t both report syntax ok. My
problem is when a user pulls up the site instead of the html translated in
to images, links, basically the web page, they get a directory listing of
the files in the /usr/local/www/data directory. Any ideas?
Thanks.
Dave.