Macro- Code To Transfer Data From Multiple Workbooks Within Folders

I have been given the following code to transfer data from multiple workbooks within folders and subfolders to retreive the same line of data from each of the workbooks and place them in a master workbook.

the folders are set up as follows,

there is a main folder, (a yearly folder)
within this are 12 monthly folders (named January to December)
within these are four weekly folders (named week 1 -week 4)
contained within these weekly folders are the workbooks that i wish to copy data from.

for example a1 - k1

the code i am using transfers the file names but comes up with #REF! instead of transfering the data

Here is the