Hi, I discovered where the problem was. It happens in the timezone-make-date-arpa-standard when a mismatch happens between the timezone, the locale settings and the automatic emacs language configuration.
I removed an old automatic configuration from my .emacs* files, and do not have this problem anymore. I feel that Emacs should do something about that mismatch. Sincerely, -- Arnaud Février fevrier À iut-gtr.univ-mrs.fr