Having recently setup a Proliant ML110 G5 Server with Windows 2003 SBS we encountered an unknown device in the Device Manager. The reason for this was that we prefer to blow away the OEM setup and rebuild from scratch. That way we get the server exactly the way we want it. This is a bit of a pain since you need to reload all the drivers manually. Everything seems OK except there is one item in Device Manager with Unknown Device Properties. The details of this item have a Device Instance ID of ACPI\IPI0001\0 and Hardware IDs of ACPI\IPI0001 *IPI0001.
Turns out that this is for the Remote Lights Out board (RILO) even though one isn't install in the server. Even better, there isn't a driver listed for the device on the HP drivers page for the ML110G5! Turns out you have to go back to the ML110G4 page where the RILO driver is located. You can also get there directly by clicking here
Boy, they certainly make it hard don't they?