You said it works without the raid right?
I wonder if its a compatibility problem with the controller.
Try building the mirror with windows 7. I think Windows 7 supports software raid doesn't it?
Apparently it doesn't. Client just called me and says she gets the same errors, including a bluescreen. Im gonna take the computer in again and look at the blue screen.
She was able to get inside Windows once and she got "Explorer has stopped working" and after some seconds a bluescreen, other time it comes just as she is starting to boot.