The picasso is different, the seat belt pre tensioners are located in the inertia reels rather than the stalks on the seat base so there are no connections under the seats for them, only connections for the side airbags.
These are all comunication fault & none point to a specific circuit like a pre tensioner or airbag so for the moment i would rule out any of the pyrotechnic components. Does everything else electrical on the car work ? does the car have anything fitted to it that is not standard ? eg different radio, alarm or handsfree kit ?