i've discovered its only whilst downloading also, not while just seeding only, if that helps.. (ie paused all downloading torrents and left seeding ones running)

the deb package from you guys.

I am also having a similar problem, except using ubuntu hardy, version 0.5.8. I have disabled all plugins and it is still using 100% cpu.This only happens while torrents are running, when they are paused cpu usage returns to normal.