From the preferences|download menu, change the "Save incomplete downloads to..." option to a directory on your D: drive.

Then, open up the 'resumeinfo.txt' file in your XoloX program directory and globally search/replace all of the "C:" path's with "D:" and the new path.

Be sure to move all the partials from C: to their new directory on D: before starting XoloX!

-J