Hi, thank you for your answer.
So, this morning.... Cardapio works well !
don't know exactly why... The 2 python's modules were already installed in synaptic.
The command "cardapio show" works directly in a xterm... and then works direcly in the unity launcher.
The only thing I do between my bug report and this morning was to log me for the first time both with gnome3 and gnome2 environment (just for testing)...