Q. Are there any rules about mixing Microsoft Systems Management Server (SMS) 2003 and System Senter Configuration Manager (SCCM) 2007 sites?

A. Yes. With SMS and SCCM, the parent site must always be the same or higher version of its children. This means if you have a mix of SMS 2003 and SCCM 2007 sites, then the SMS 2003 sites would have to be children of SCCM 2007 sites. You can't have a SCCM 2007 site as a child of a SMS 2003 site