Simulink model to c code generation; ti c2000 launchpad piccolo F28027, pmsmfoc.slx, error with hidden block

I have installed Matlab 2018b, and tring to codegen with a model which is downloaded from mathwork.

This model is called "c28027pmsmfoc.slx", which is used to control the PMSM with FOC. when I setted the configuration and start to generate, the matlab returns an error :

and the "SCI Trnsmit" is showning like follow:

I don't understand what the error message means with the "hidden block" , and how I would be able to fix this problem.

BR

George