I am having a problem with this as well. Moving them to the END of the drive as it specifies (its all free space there). Whats odd is it seems to move the first file there fine, but then forgets that its supposed to be at the end of the drive, and moves random parts of it back forward, and so forth... it gets stuck for a while then proceeds to another file, and sometimes gets stuck infinitely.
It is a very odd problem but its defiantly not working as it should...