Wordtube freezes when I add a preview image

I know this topic has been mentioned below but is has a ‘resolved’ state, but it aint so am re-opening it.

Anyway, I’m using the latest WordTube plugin which works fine until I go to add a preview image to the video. You can see the preview image in the player OK but this causes to the player to lockup and freeze and you can’t view the video at all. When you take the preview image out again everything is hunky dory. What’s the crack???