My own syntax which is working flawlessly is slightly different to yours. The relevant section is:
Is this similar to what you are trying to accomplish? This is with:
# Watch a directory for new torrents, and stop those that have been deleted.
schedule = watch_directory,5,5,load_start=/home/andrew/.rtorrent/*.torrent
schedule = untied_directory,5,5,stop_untied=
# Move the completed torrents to~/downloads:
system.method.set_key = event.download.finished,move_complete,"execute=mv,-u,$d.get_base_path=,~/downloads/;d.set_directory=~/downloads/"
andrew@skamandros~$ rtorrent -h | head -n 1
Rakshasa's BitTorrent client version 0.9.2.