Structural arrays on parfor loop

Hello,

I am using a parfor loop in the following nested structure:

parfor 
    for 
        for
            
        end
    end
end

I am also importing a few variables as structural arrays into my code and this must be reason why I'm receiving the following message:

%An UndefinedFunction error was thrown on the workers for 'x'.  This might be because the file containing
%'x' is not accessible on the workers.  Use addAttachedFiles(pool, files) to specify the required files to
%be attached.  See the documentation for 'parallel.Pool/addAttachedFiles' for more details.

where x is a variable that receives a value of a cell out of a structural array.

STEP 1: To avoid this I replaced every structural array defined variable into a double outside the parfor loop. The error remained.

STEP 2: As suggested, used the command

addAttachedFiles({'file1.mat','file2.mat'})

to specify the structural array files inside the parfor loop even though I had already gotten rid of them before. The error remained.

Any suggestions?

Thanks in advance,

Kyriakos