How do I resolve these errors in MATLAB image processing while using command impixel

I am new to MATLAB image processing and trying to extract image features on the basis of colour thresholding but unable to go further. Right after selecting image pixel and I receive the following errors:

Error using getpts (line 174)
Interruption during mouse point selection.
Error in impixel>parse_inputs (line 199)
        [xi,yi] = getpts(ancestor(h,'axes'));
Error in impixel (line 76)
[a,cm,xi,yi,x,y] = parse_inputs(varargin{:});
Error in featureextraction (line 5)
pval = impixel(a);

Here is my code:

oneToolImg = 'E:\Ujala Documents\hfu ss\forschungspraktikum\oneTool.jpg';
a = imread(oneToolImg);
figure(1)
imshow(a)
pval = impixel(a);
tool = (a(:,:,1)>91) & (a(:,:,2)>82) & (a(:,:,3)<252);
figure,imshow(tool)