In case someone wonders what went wrong:
Updating lighttpd to v1.4.30 overwrites the file index.html (and breaks your website)
Updating mutt to 1.5.21 (2010-09-15) overwrites the file /etc/Muttrc (and breaks mutt)
Admittedly it's not the first time I got tricked by this but it is non-standard behaviour on other distro's.
/emgi