Error using FFT v7.1 in matlab 2013a System Generator

Hello,

I am using MATLAB 2013a , ISE 14.7 to simulate a project using System Generator and my device is Spartan 6. In my project i need to use FFT Block , and i wanna use FFT v7.1. As I design my simulation and then run it , suddenly MATLAB crashes and then it closes.

I don't know if the problem is for my simulation or it is because of my applications version compaibility problems.

And also I'm using all of them on Windows 10.

If t is needed , tell me to attach my .slx file.

many many thanks....