Thanks for replying Klaus. I'm using krpano 1.1.7 - from my limited testing the lines are only appearing when viewing the HTML5 version using Safari on desktop computers (Mac OS) - I can't see the lines on iPad or iPhone. The lines don't show on all the cube face edges, just one edge of the top face for example. The same result is showing on older versions of Safari that I have set up here: 5.0.6/5.1.7 and a later version 7.0.3.
Best Regards, Neil