I've been trying to set a custom include path as described in http://wiki.dreamhost.com/PHP.ini#PHP_5.3. I am using PHP 5.3.5 FastCGI, but the custom path does not show up when I do a phpinfo(). Nor does it work when I try to include scripts from the local directories I added.
Please ignore. Suddenly, a day after making the changes, all my scripts simultaneously broke from an error in the phprc file. After fixing the error, everything worked. It was as if someone turned on a switch labelled, "read supplementary ini file."