PHP System command - need help

Hello. I'm trying to issue a system command via a php3 web page that runs a script. Unfortunately, the script seems to bomb out ( it triggers a secure copy and fails to create a SSH directory ). I'm trying to find out what user it is executing this as and remedy it so the script will operate properly. The script functions fine as run through my machines cron, so if there is a way to execute a command from a php page as root, I'd appreciate knowing how to do that as well. Any help is appreciated. Travis