DO NOT CLICK "OK" on the message as this will close also deluge but when open deluge it will check every torrent to see if the "data" are there.
P.S. Hope that it helps a bit

Also to minimize these errors, try not to use lots of torrents with deluge, it isn't much stable for multiple torrents(keep less than 4) and don't play with the settings all the time as this sometime gives you the errors