You have to try the latest Version of Deluge or Upgrade your old version. It's solve your problem of crashing.You can download latest version from the
websites.still you have facing problem call the vendor.

I have also faced this kind of Problem.It's happens due to the Problem of session .You have to clear the cookies of the browser you use.
Other is due to the ISP(Internet Service Provider) If you use static IP(Internet Protpcol) then this kind of Problem happens.Change the IP you are using.

I have never seen that kind of problem in downloading torrent files.whenever I have downloaded the torrent files it has always his default extension of particular file like .mpg, .avi ,.divx if video files.If any application then it has a .exe extension. It has a never .torrent file extension.