kmail crashes in 9.1

I've been using kmail for a little while--since I received and installed 9.1--but the last 2 days when I logged out of kmail I got a crash message. I don't know if this has any relation to the inability to keep messages in a self-made folder in kmail, but it is annoying. Linux things aren't supposed to crash, I read. On the net, there used to be, apparently, a way to use Eudora 5.1 in Linux. Does anyone know how? The site is no longer available. --doug