Release file expired, ignoring http://data.alienvault.com/mirror/squeeze_security/dists/squeeze/updates/Release (invalid since 242d 14h 31min 53s)

I just finished the installation of AlienVault v4.2.0 Community edition and I was trying to update the OS. When I sent the classic Debian update command " #apt-get update" , it sent me back this message :)

Release file expired, ignoring http://data.alienvault.com/mirror/squeeze_security/dists/squeeze/updates/Release (invalid since 242d 14h 31min 53s)

It's very easy to solve this. Just a misreading. All you have to do is using the Alienvault's update command instead of classic Ubuntu command.

#alienvault-update