====== Locale is missing, how to create it ======
when you get an error like this (seems to happen on all my fresh ubuntu installs) 
<code>
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
	LANGUAGE = (unset),
	LC_ALL = (unset),
	LC_PAPER = "de_CH.UTF-8",
	LC_ADDRESS = "de_CH.UTF-8",
	LC_MONETARY = "de_CH.UTF-8",
	LC_NUMERIC = "de_CH.UTF-8",
	LC_TELEPHONE = "de_CH.UTF-8",
	LC_IDENTIFICATION = "de_CH.UTF-8",
	LC_MEASUREMENT = "de_CH.UTF-8",
	LC_TIME = "de_CH.UTF-8",
	LC_NAME = "de_CH.UTF-8",
	LANG = "en_US.UTF-8"
    are supported and installed on your system.
</code>
you need to simply generate the missing locae by runningn 
  locale-gen "de_CH.UTF-8"
problem solved ;)
===== CentOS / RedHat solution =====
  localedef -v -c -i en_US -f UTF-8 en_US.UTF-8