perl: warning: Setting locale failed

I get this error while updating and installing software : perl: warning: Setting locale failed

perl: warning: Falling back to the standard locale ("C").
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = (unset),
    LC_ALL = (unset),
    LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

As root enter the following command in terminal and reboot your server.
echo "en_US.UTF-8 UTF-8" > /var/lib/locales/supported.d/local dpkg-reconfigure locales