I've tried it in both the free and the pro versions and the results have been the same. Of course I didn't expect it to work in the free version anyway.
Perhaps the developers would prefer that we use a Management Server running the Avast Distributed Network Manager (ADNM), but short of that I can't seem to make it work with version 5 like I used to do with version 4, and since I've still not received a response from the support ticket that I submitted regarding this issue I can only speculate.
Either way, at this time, my choices are to go back to version 4, or update each PC manually. Neither solution gives me much joy.