Hi Paul, it is most likely because you have not set up a connection within Qlik Sense, so the application does not know what file location you are talking about.
While in the data load editor you will have to create a new connection to the specific folder and then load it in from there.
Also an Easier way to show the YEAR from a date is to use the Year() function
i.e. Year([Due Date]) as YEAR
Hope this helps, let me know how you get on.