And more, since you mentioned mdadm and dmraid:
http://forums.gentoo.org/viewtopic-t-888520-start-0.html
It sounds like you need to pick one, and the one to pick is mdraid, and expressly disable dmraid.
I personally would consider that you go into BIOS and blow away this RAID. Recreate it from scratch, and partition with gdisk from a LiveCD (e.g. gdisk is on the Fedora 17 livecd). Then install Windows. Then go back to the LiveCD and confirm that the GPT is still OK. Then install linux.
Chris Murphy