I am also getting this, it was working fine, i then connected a new 10m hdmi cable to my projector and at first the wdtv home screen had a green tint. It then lost signal, came back 10 seconds later still with the green tint, then went away again.
I also had my headphones connected to the av out on the wdtv for about an 2hours, just read now its not a good idea.
So i unplugged the 10m cable, connected my 1.2m cable and it just doesn't output anything now.
I have tried a combination of hdmi cables and 3 different tv's 1 Panasonic plasma, one Samsung LCD and one Sharp LCD. Connecting to the composite works fine.
I tried connecting the composite, going into the video/audio settings on wdtv and changing the output to hdmi/720p, but it just goes back to composite.
I have also tried the 1 second reset and a factory reset.
Any ideas? I've had to borrow another wdtv live which works fine.