When installing Windows on IBM, without using IBM ServerGuide, you’ll sometimes end up having two unknown devices in Device Manager:

and:

To deal with the first one, see document MIGR-43764 and download the driver mentioned there (it’s called “25k9219.zip”).
The latter can be fixed by installing the “IBM Active PCI Software”, you can find it on your server’s support page, e.g. here (“90p4169.exe”).

Also, document MIGR-51940, Installing Microsoft Windows Server 2003 version 1.0 – Servers, proves useful.

And a last bit: if you’re in a hurry or haven’t got the CD handy, ServeRAID Manager Software can be installed by simply copy/pasting its folder from another server. It usually works. 🙂