For some reason, PHP scripts will not run unless the web root (Htdocs directory) can by read by the current user under "Web/FTP Server > Web Server > Permissions" in HostPilot Control Panel. The current user is whatever user is running the script. Usually, this is the anonymous user, unless your script prompts for a password before running.
Support engineers and developers will work to find reasons and solutions to this problem, if they exist. Comments to support would be appreciated about this or any other issue that arises as we test PHP.