This is a brand new system - never used before. It has an Intel MB, 2GB RAM, dual 160GB SATA drives mirrored. Set-up files load then present a warning that WHS cannot continue with the installed drives. The actual message is "Hard drive capable of hosting WHS was not found. Would you like to load additional storage drivers?"
Split up the RAID and try installing then. From what I have read WHS does not currently play well with RAIDs. I have my WHS box set up with dual 160GB IDE drives and a 40GB IDE drive, your specs should work.