a $> chrgrp mail /var/run/courier as root avoids this error message during startup of /etc/init.d/courier : messages:2013-09-03T19:28:20.000+02:00 trinity courierfilter: /var/run/courier/courierfilter.pid: Permission denied
in 0.71 (now stable) directories get created by the init script with the correct permissions
yep - so I'll close this bug