Procmail dies..

For some messages, for some users particular, Procmail dies
with signals 12, 13, 212 or 213. I can send mail to the user with
procmail, so I guess it's not about being able to write to users mailbox. The
users are not using any kind of .procmailrc. The same messages keep killing the
procmail while others go through. Any ideas?

-- 
                                                Antti Rytsölä
                                                Data Link Connections
                                                raccoon(_at_)dlc(_dot_)fi