I can't get our PCs to work using the Power On function.
I have the same issue, but it is our school setup thats blocking it.
I believe the Power On uses Wake-On-Lan which is often blocked in organizations. It uses a "magic" packet that is sent to the machine to wake it up. Firewalls/Network Switches often block the port (UDP 7 and 9).
You also have to ensure the Wake-On-Lan feature is enabled in the BIOS of the PC.
Third thing is to remember that Wake-On-Lan uses MAC Address so I suspect you need to add them all into the config file (Locations/PC Names bit)