anything wrong with the gabor filter parameters

I am trying to implement Gabor filter bank. using code from matlab central. My problem is fro all filters I am getting same response. parameters used are

sigma= 0.2; psi= 1 gamma=3 n1=3; lambda=[-5,10,15] n2=4; theta=[0;45;90;135;180]

what is wrong with these parameters? please suggest.Thanks in advance