Multinomial logistic regression code

I am new learner in the field of classification, and am stuck with a problem while implementing logistic regression:

My data set consists of about 315 measurement, with 19 features. I implemented logistic regression model.when i run my code error occure in these two lines.

Error in main function

    plotdecisionboundry(theta,X,Y)  %error

Error in plotdecisionboundry function

   Z(i,j)=mapfeature(u(i),v(j))*theta;   %error