Warning: Integer operands are required for colon operator when used as index ???

My code is showing the following:

Warning: Integer operands are required for colon operator when used as index

Y=int32(noise);

Y=int32(yn);

X=int32(xn);

[xn,yn] = ginput(1);

noise = img((yn-2):(yn+2), (xn-2):(xn+2));

noise = mean(noise(:));

img = img - noise;

It is showing the error in 5th line noise = img((yn-2):(yn+2), (xn-2):(xn+2));

Please help

[Walter Roberson]

duplicates http://www.mathworks.co.uk/matlabcentral/answers/107123-code-shows-integer-operands-are-required-for-colon-operator-when-used-as-index