Unpacking squid3 (from .../squid3_3.1.19-1ubuntu3_i386.deb) ...
Selecting previously unselected package squid.
Unpacking squid (from .../squid_3.1.19-1ubuntu3_i386.deb) ...
Processing triggers for man-db ...
Processing triggers for ureadahead ...
ureadahead will be reprofiled on next reboot
Processing triggers for ufw ...
Setting up squid3 (3.1.19-1ubuntu3) ...
/var/lib/dpkg/info/squid3.postinst: 1: /var/lib/dpkg/info/squid3.postinst: cannot open /etc/squid3/squid.conf: No such file
dpkg: error processing squid3 (--configure):
 subprocess installed post-installation script returned error exit status 2