how to extract frames from memory and store it in a folder?????

i need to extract frame(obtained from this code below) from memory to a particular folder, so that i cd further process it

     vid = videoinput('winvideo',1);

preview(vid);
set(vid,'TriggerRepeat',Inf);
set(vid,'ReturnedColorSpace','grayscale');
vid.FrameGrabInterval = 1;

% Set value of a video source object property. vid_src = getselectedsource(vid);

 set(vid_src,'Tag','motion detection setup');

 disp(sprintf(' FRAMING START from VIDEO')); 

 start(vid);

 while(vid.FramesAcquired<=50) % Stop after 100 frames

    data = getdata(vid,2); 
     diff_im = imabsdiff(data(:,:,:,1),data(:,:,:,2));
      imshow(diff_im);
end

}

for making a folder and storing frames(from memory) to this folder

m tring this code but these errors r found

1) permission is denied for MKDIR 2) undefined function fullfile..

outputFolder = fullfile(cd, 'Test');

 if ~exist(outputFolder, 'dir')

 mkdir(outputFolder);

end

outputBaseFileName = disp('Image %3.3d.jpg',vid);

disp(outputBaseFileName);

outputFullFileName = fullfile(outputFolder, outputBaseFileName);

 plz help so dat i cd store these frame to a folder