Paths are correct then, and it shouldn't have problems with file reading. In this situation it's hard to guess what's wrong. You might try to organize the directory like I have done in the Release package (you would need to find and copy Qt libraries (from it's installation directory) and copy the executable from build directory).
You may also switch off Shadow build, and put data and flags folders inside
NTScout-master/source/ntscout/ and then try to compile and run it.
Or perhaps user whitewind
(196796) could help you as he managed to compile and run it on mac.