Do /var/spool/postfix/var/run/saslauthd and /usr/sbin/saslauthd exist?
Does
Code:
start-stop-daemon --start --quiet --pidfile /var/spool/postfix/var/run/saslauthd/saslauthd.pid --name saslauthd --exec /usr/sbin/saslauthd -- -a pam -c -m /var/spool/postfix/var/run/saslauthd -r -n 5
show any errors?