Reset locale in debian under Squeeze

I have problems with locale in debian. I tried many thing but it doesn't anything for me :

locale -a

locale: Cannot set LC_CTYPE to default locale: No such file or directory
C
POSIX
en_US.utf8

I try to set en_US.utf8 without success with this :

dpkg-reconfigure locales -plow
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = "en_US",
    LC_ALL = (unset),
    LC_CTYPE = "UTF-8",
    LANG = (unset)
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
/usr/bin/locale: Cannot set LC_CTYPE to default locale: No such file or directory
/usr/bin/locale: Cannot set LC_ALL to default locale: No such file or directory
Generating locales (this might take a while)...
  en_US.UTF-8... done
Generation complete.
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = "en_US",
    LC_ALL = (unset),
    LC_CTYPE = "UTF-8",
    LANG = (unset)
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
    LANGUAGE = "en_US",
    LC_ALL = (unset),
    LC_CTYPE = "UTF-8",
    LANG = (unset)
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

After reboot, i try to use a perl script :

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

Here is my /etc/default/locale config file :

cat /etc/default/locale 
LANG=en_US.UTF-8
LANGUAGE=en_US

Any idea to solve this (stupid) problem ?

Thanks