[imp] language problem

[Cyril AGRA]

Hi,
I'm install a new server B Debian 4.0r1 (i386) with apache2 
2.2.3-4+etch1, php5 5.2.0-8+etch7. I'm getting my webmail (Webmail 
Edition 1.0) witch is install on another serveur A with the same 
configuration like B (same release debian, apache2, php5). However the 
webmail on my new serveur B is in English not in French. Why such 
behavior ? Is it possible to force the language ?
Thanks
Cyril