first of all , it is in wrong section.. this belong to help desk...

as much as i know.. there is no option in utorrent that automatically deletes the torrent... either u or someone using computer deletes the torrent file or data manually....

check the log tab of utorrent and see what is happening... or paste log over here

lastly, it is always better to re-read whatever you write... it makes things clear and simple for others ie correctly written stuff makes it easy to understand...