Comment 1 for bug 776945

Thank you for using Ubuntu and filing a bug. By default, isc-dhcp-server's dhcpd will use /var/run/dhcp-server/dhcpd.pid, and this is allowed by the AppArmor profile. /etc/dhcpd.conf is also a non-default (though common outside of Ubuntu) location for the configuration file, so it appears you are using non-default configuration options (and therefore either need to adjust the AppArmor profile, or your configuration). Can you attach your /etc/dhcpd.conf file?