I have exactly the same problem! I get a black screen, speed is high. First I had only audio and no vido, now I also have no audio anymore. What can I do to fix this? I already pwoer off the slingbox and power on again, still the same problem. The TV give video and audio no problem. All the cables are perfeclty in (acttually no one touched it so that can't be the problem).
Problems started after plugin update.
I hope someone can help.