Posting this as it may be of help to others.
I had the above error. Tried everything suggested in the forums but to no avail.
Eventually tracked it down to the fact silverlight was not running after I installed a new Creative Sound Card.
I was using either the DTS or Dolby enhancement on my soundcard and turning these off immediately fixed the problem.
Solved! Go to Solution.
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.
I checked the system requirements of silverlight and the surface 3 meets the requirements. I ran the fix it tool at https://support.microsoft.com/en-gb/kb/2608523 (also stated at https://community.bt.com/t5/Watching-BT-Sport-via-the-App-or/Top-tips-for-Silverlight-Issues-with-wa... ) restarted the surface 3.
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.