The incomplete folder must be in the same location as the main save folder, but one level above if that makes sense. It is created automatically by Limewire.
So the only way to move it is by moving your save folder.
I'm curious why you would want to move it, but if you want to move the save folder as well it would make sense
Btw, if you move it you may not be able to re-start incompletes from where they left off.