Paragon Camptune says "Resizing operation failed. No free space" when there is space

I am having a problem in resizing my 2 volumes on my Macbook Pro (2016, 1TB HDD) using Paragon Camptune. I have used this app before and it worked well.

At the moment, when I try and resize the volumes I am getting this error message: "Resizing operation failed. No free space (cannot create partition of requested size)". See screenshot:

http://i68.tinypic.com/1zf0o4x.png

However, looking at the volume sizes in Camptune, it does appear that my "Macintosh HD" does have free space - 100.93GB to be exact. See screenshot:

http://i64.tinypic.com/2ij6m9e.png

I tried to move just 25GB or so of space to the Bootcamp partition, but am getting this error message. Any help appreciated!