Simulink Accelerator mode hangs

I have a Simulink model with 2 different S-Function blocks. I'm not sure that using such blocks may be important or not. If I try to let it run in "Accelerator mode" it gets frozen before executing the 1st step; it seems that the process hangs somewhere on the MS SDK side (mostly at linking). I'm using Windows 7 and Matlab 2015B. Even worse, that in this state it is not possible to stop either Matlab or Windows (Windows shut down gets frozen at "Shutting down" message), unly the power button helps. I have found this old article, but it didn't solve the problem (solution 1 I tried but without success): https://de.mathworks.com/matlabcentral/answers/102249-why-does-code-compilation-hang-when-generating-code-for-a-model-using-the-simulink-accelerator-6-0

Could somebody help me?

Thanks

G. Barta (Mr)