the preview link on the Templates page has actually been just introduced with the latest update - in previous versions you could only preview listings, not templates.
But a blank page usually comes with a meaningful error message in your server's error log. I need you to check that one first - there could be anything from lacking free memory to errors that point to compatibility issues with other plugins.
Since I can't recreate this issue on my testing site (and you already disabled the plugin and reverted to the default WP theme), I can only guess it might be something in your listing template's code to cause this.
So if you don't find anything in your error log, please create an account on your site and send the login details to support at wplab dot com - or use the contact form on that page. I'll check your listing template - and see if I can recreate the same issue using your template on my testing site.
P.S: I'm afraid there are no download links for previous versions. But issues like this generally shouldn't take very long to solve...