I've installed the Picker, and I can run the Picker of Malcolm but absolutely nothing happens when I click on. It's only write on the Script Editor :
// Error: line 1: No object matches name: malcolm_v200:faceControls //
What can I do to fix this ? Thank you in advance

Sounds like you might have opened or imported the rig instead of referencing. You have to reference it with the namespace. See the youtube video link on the info page.