Well I found the problem, hopefully it can help others...
The problem - I was missing one OpenCV library when compiling. So I replaced "opencv_core opencv_highgui" by "opencv_core opencv_imgproc opencv_highgui" and everything works.
So although I was able to compile it one of the dependencies was missing - I guess something has changed in OpenCV cause these sources worked perfectly (even with build) with older versions of the OpenCV.