Error " Undefined function 'minus' for input arguments of type 'cell'

Hi,

When I try to select the option ' Search how to include regressors in the nonlinear block ' using the system identification tool box i get the error ' undefined function 'minus' for input arguments of type 'cell' '

Maybe I wrote the custom regressors badly ?

Here they are :

    c2 = customreg(@(x)((x>1.3) || (x<-0.5))*x,{'u1'},0);
    c1 = customreg(@(x)max(min(x,111.5),-104.3),{'y1'},1);

Please help me,

Stevi