Steps to reproduce (try to use a large file)
1. Complete a torrent DL. No need to seed afterwards
2. Move the torrent to a new location, preferably onto a different disk/partition than is currently being used so it acts more like a copy.
3. Before the move is completed, delete the torrent (not the files) from ktorrent
4. When the move completes, ktorrent crashes.

I don't have a backtrace due to not have debugging symbols, but I suspect it crashes because it's trying to update the UI for the new file location, but the torrent it wants to update doesn't exist anymore.

I will investigate it tomorrow.

This doesn't happen with latest SVN, so the problem is most likely fixed.