problema con avvio di squid!!!

[cucumiao]

ciao a tutti ho appena insallato squid su ubuntu server 6.06, ma all'avvio mi da il seguente errore!!!
cucumiaoserver@cucumiaoserver:~$ sudo /etc/init.d/squid start
* Starting Squid HTTP proxy squid * Creating squid spool directory structure
FATAL: Could not determine fully qualified hostname. Please set 'visible_hostname'

Squid Cache (Version 2.5.STABLE12): Terminated abnormally.
CPU Usage: 0.010 seconds = 0.010 user + 0.000 sys
Maximum Resident Size: 0 KB
Page faults with physical i/o: 0
/etc/init.d/squid: line 64: 7399 Aborted $DAEMON -z
FATAL: Could not determine fully qualified hostname. Please set 'visible_hostname'

Squid Cache (Version 2.5.STABLE12): Terminated abnormally.
CPU Usage: 0.020 seconds = 0.000 user + 0.020 sys
Maximum Resident Size: 0 KB
Page faults with physical i/o: 0
/etc/init.d/squid: line 64: 7401 Aborted start-stop-daemon --quiet --start --pidfile $PIDFILE --chuid $CHUID --exec $DAEMON -- $SQUID_ARGS </dev/null
[fail]

come potrei risolverla????

[cucumiao]

# TAG: visible_hostname cucumiaoserver
# If you want to present a special hostname in error messages, etc,
# define this. Otherwise, the return value of gethostname()
# will be used. If you have multiple caches in a cluster and
# get errors about IP-forwarding you must set them to have individual
# names with this setting.
#
#Default:
# none
questo e il file squid.conf che ho modificato ma senza successo!!! dove sbaglio???