About the translation problem (sorry the other subject in this post!) :
I think I understand the problem now. It's not the .mo file which is a problem but the default.conf (where menus are kept obviously) and the other files located in my profile. When Codeblocks was first installed, I was an administrator. When I installed the .mo file, I was already a standard user. Obviously, I had only read rights on those files and codeblocks was then unable to reset them. But after setting me as a proprietary of those files (with the help of an administrator!!), deleting them and restarting codeblocks which recreated them, everything is good now.
gd