check here
http://www.betaone.net/forum/thread-16151.html
I had the same issue with a 200GB harddrive.
Try this first though, there is a registry patch to enable 48bit lba stuffs (large harddrive patch) its just a .reg file, not sure where to find it but, it shouldn't be to hard to find, then if all else fails read the above post, it can be a little difficult to figure out!