I am having this same EXACT problem. Experimenting, I exported to AVI, generated mono file per track, and rendered uncompressed - I ended up with a viewable file, but it was weird. It was a split screen, split vertically, showing the video in both screens, and there was no sound.
I would love to use Lightworks for editing, but until some of these issues get settled, I'm forced to use something else while I wait. I will be eagerly waiting and checking back often.
@HayManMarc, if you bothered to use the forums Search function you'd find out that you have to open the project card and, under the "Video" tab, change "Display optimisation" from 'Fields' to 'Frames' to avoid split screen.