Must be an error in the addon - it probably hits an infinite loop.
It works fine when you drag, move and drop the player sprite very quickly and points are far away from each other. But if you move it slowly and the distance between points is small, it freezes.
So I guess you need to filter the path - remove unnecessary points.
Here is a quick fix:
dropbox.com/s/hvp8jmej1dd9f5i/test_spline.capx