I am processing data using a Matlab code that I did not write, and I have minimal experience coding. I am getting and error “Unrecognized field name ‘rowheaders'”

%emission wavelengths 
emw=A.rowheaders; %25Jan: Taking the rowheaders from all of the imported EEM matrix. This has the emission wavelengths listed. (245.91 to 826.826 in approx. 2.33 nm intervals). Already formatted as a column.
emw=emw(2:end,:);

Above, A is the variable the data was assigned to.

Is .rowheaders supposed to be defined in the code before this point (it currently is not), or is this a pre-existing field name that Matlab should know what it is referring to?

I have tried looking this question up, but nothing has been helpful so far, although it may be due to my lack of understanding of Matlab and this script.