well just try to install it from windows. I mean, if u didnt do anything to the partitions or something, ur hdd wil already be properly set up for media direct. Just go in windows, pop the cd in, and if it doesnt give any error that it is not partitioned properly, then just reinstall it. It wont do anything to the ur data on ur drive.
If that doesnt solve it, then i guess the only way is to start from scratch, which means having media direct format everything when u boot the cd.