need help in solving error in code of "cepstral pitch"

from the link "http://in.mathworks.com/matlabcentral/fileexchange/45558-cepstral-pitch" i downloaded codes for cepstral pitch detection and tracking. the main code "cepstral pitch GUI25.m" runs and GUI is displayed.next step audio file plays but i am getting error when i click button "Run cepstral pitch". error displayed as follows:

*"Undefined function 'srconv' for input arguments of type 'double'.

Error in Callbacks_cepstral_pitch_GUI25/setup_cepstral_pitch_detector (line 449) *y=srconv(y,fs,fsd);

Error in Callbacks_cepstral_pitch_GUI25/button9Callback (line 426) [n,p1m,nl,c1m]=setup_cepstral_pitch_detector(xin,fs,fsd,imf,pthr1,nfft,... * Error while evaluating uicontrol Callback "*

Anybody can help me pls?