My system is
Linux bermudahonk 188.8.131.52 #4 Mon Oct 2 14:44:52 CEST 2006 x86_64 GNU/Linux
Over the last past days i always got segfaults trying to update the wordlist using it on my spam folder. So I took closer look on those mails and found the reason. Every mail that has an apostrophe in the mail atribute "From:" (which as I think isn't right in the first place) bogofilter crashes when used to create the worldlist like
find $HOME/Mail/Spam -type f | bogofilter -v -s -b
I've attached one email it does crash with.