The additional config files used by freepbx (/etc/asterisk/) have not been created by the installation, which has been apparently correctly completed. I have created the additional config files manually, but they are not modified when I add / change / remove something, in the freepbx web interface. MySQL works perfectly. And I don’t forget to apply changes each time I modify something.
Sleepless night are coming.
Thanx for your help.