You have a variable in your workspace named xlabel.
Rename that variable.
Example of this error:
xlabel = 'apples';
xlabel('difference')
% ERROR
% Index exceeds the number of array elements (6).
This because 'difference' is converted to a numeric matrix
double('difference')
ans =
100 105 102 102 101 114 101 110 99 101
And since your label only contains 6 characters, the error is caused by trying to access the 100th element.
xlabel = 'apples';
xlabel(100)
% ERROR
% Index exceeds the number of array elements (6).
