If like me you just have upgraded your Debian system to Lenny, you probably encounter the following warnings while launching perl:
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LANG = “fr_FR.UTF-8″
    are supported and installed on your system.
perl: warning: Falling back to the standard locale [...]