I’ve re-installed everything from the start (again).
Now it works quite well!
Joypad buttons are not 100% accurate (SNES pad button “y” is also “left-button” at the same time) but I have no more time to spend on it, really.
I don’t understand how the same process can bring to so many different results.
I would like to thank everybody for the support, especially elbotija that save me tons of work hours posting his configuration file.