I just executed "pacman -Syu" on my pink Pogoplug and the db package was updated to 5.3.15-1.
Since then postfix has a problem.
/var/log/mail.log is filled with the following messages:
postfix/master[1234]: warning: process /usr/lib/postfix/smtpd pid 21180 exit status 127
postfix/master[1234]: warning: /usr/lib/postfix/smtpd: bad command startup -- throttling
Apparently postfix depends on libdb-5.2.so and that file is no longer present on my Pogoplug since the db package update.
To fix this, I had to go into /usr/lib and
ln -s libdb-5.3.so libdb-5.2.so
Then "/etc/rc.d/postfix start" worked again.