Thought I would chip in with my experience of this error. I installed silverlight via Windows Update on my Microsoft Surface 3. Using firefox when I signed in to BT Sport and attempted to watch programmes on demand I recieved error 3142 VC019. The live stream of any BT Sport channel would crash firefox.
Using Internet Explorer, only the video would load but the video plays as if it slow motion footage. I also noted that my no audio played using any application on my surface 3 and only a restart would resolve this.
When I now watch any BT Sport programme on demand or the live stream in Internet Explorer there are no issues at all. In firefox the first few seconds of audio play for on demand programmes and then the loading circle appears indefinetley. The loading circle appears indefinetley for any live stream. I will contact Microsoft / Mozilla about this issue to establish if there is a solution.