This has happened to me recently also. I installed deluge from the ubuntu repos. Perhaps it is a bug. I don't have 100 torrents, so no big deal for me.
Deluge 0.5.8 / Ubuntu 7.04 - something similar happened to me.
My PC crashed when a torrent was at 80-90% and when I restarted Deluge, it restarted the download from 0%. Interestingly, my ratio was preserved, just not the already downloaded data.