VO Web Servers
From UABgrid Documentation
Configuring a CentOS 4x Apache config
Remove the welcome.conf file
If you don't want to enable directory indexes when there isn't an index.html in a directory, you will need to remove or comment out the contents of the conf.d/welcome.conf file. If not, this will force the default "welcome" page to be displayed. Note, this may be a security consideration, so don't just blindly do it. It's documented here to avoid frustration if you know you've allowed directory indexes via Options Indexes or simile but you still don't see them.
Explictly install php-mysql
You will probably need to explicitly install the php-mysql rpm to enable php tools access to the database.
yum install php-mysql