Could you please try to associate Keyb_1 and Keyb_2 to the Local GP Port ?
EDIT: using the Local GP Port for this makes the Script Logger message disappear. But, if you want the Gig Script to work as intended, you need to associate your Keyb_n Device Alias Names to n existing MIDI device. You can create virtual MIDI ports for this using LoopMIDI (on Win) or IAC (on Mac).