Windows 7 is largely allergic to RAID. None of the standard troubleshooting steps work with RAID either, so we are at a loss here to help until someone familar with the dated RAID technology (rarely) steps forward.
Can you dissolve the RAID config and set one HD to AHCI to install Windows 7? The AHCI (or SATA/IDE) drivers
should be in the booted Windows 7 installer, or they are on the Support Downloads page for your model mobo.