Falls eine dieser Fehlermeldungen:
manconv: can't set the locale; make sure $LC_* and $LANG are correct
oder
perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = "en_US:en_GB:en", LC_ALL = (unset), LANG = "en" are supported and installed on your system.
had the same problem. I fixed it by deleting the lines in /etc/locale.gen and removing the package locales and re-installing it
apt-get remove locales apt-get install locales
Upon re-installing you will be asked which locales to generate. I ran into some other issues because I installed the package localepurge. Remove this if you have it, it will mess up the initial locale gen. If you have other problems try
dpkg-reconfigure locales
To close off this issue and for future problems:
sudo localedef -i lang-f /path/to/charmap lang
where lang is your language (en_US)
and charmap is UTF-8,
just run locate UTF-8 to find the path.