Comment 2 for bug 748261

It's still a bug because this is happens on every ubuntu (server and desktop) I used on the last couple of years and besides during installation (where I choose English as language, UTF8 for encoding, Portuguese as keyboard layout and Europe/Lisbon for the timezone.
So it is a problem with the ubuntu installer, not a problem caused by a misconfiguration made by the user.

# locale
 locale
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=en_US.UTF-8
LANGUAGE=en_US:en
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC=pt_PT.UTF-8
LC_TIME=pt_PT.UTF-8
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=pt_PT.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=pt_PT.UTF-8
LC_NAME=pt_PT.UTF-8
LC_ADDRESS=pt_PT.UTF-8
LC_TELEPHONE=pt_PT.UTF-8
LC_MEASUREMENT=pt_PT.UTF-8
LC_IDENTIFICATION=pt_PT.UTF-8
LC_ALL=

WORKAROUND:

$ sudo vim /etc/environment

_ at the end of the file add: LC_ALL="en_US.UTF-8"
_ or your favorite encoding

$ sudo reboot