Lightbox Video Player Black Screen

I’m running v1.7 of lightbox, recently upgraded from an earlier version but the following problem persists in Safari v5.1.10 (Firefox works fine).
Upon clicking the thumbnail of the video I get an unresponsive popup window with an unresponsive black screen, no controls evident. It does however respond to the following:
+Double clicking loads a full window of the player that works ok
+Hitting the spacebar seems to reload the video player and the play button becomes visible, the video plays subsequently as normal
I would like to know if there is a solution to this problem as I cannot expect my visitors to know either of these fixes. I would be most grateful for any assistance as I think the plugin is fantastic.
Thanks, Mark.

https://wordpress.org/plugins/wp-video-lightbox/