Looks like you've met a limitation of ktorrent. I don't use ktorrent had a quick google and it seems you can specify a directory that it can watch for new torrents which it will automatically load. So I guess you need to do two things;
1. Modify your script to move the torrent file instead of running ktorrent
mv "$*" ~/torrent-autoload/
2. Configure ktorrent to look in a specific directory for new torrent files (probably in some configuration gui)
In this scenario you need to start ktorrent manually, or you could add one more line to the script to try to start ktorrent.