Error while adding tag to time frequency source files

Hi @tmedani
Thank you for your quick reply.

The script I am using is as follows:

   main_folder = '/media/rajat/Rasendisk/lab/brainstorm_db/SOA/data/';
   conditions ={'base_no_feedback', '50_no_feedback','50_feedback','75_no_feedback','75_feedback',};

for ii = 1:length(conditions)
    filePattern = fullfile(main_folder, '*Group_analysis*' , 'Response-locked', '*smooth*');
    files = struct2table(dir(filePattern));
    sFiles = strcat(files.folder, '/', files.name);
    sFiles = sFiles(contains(sFiles, conditions{ii}));
    
    % Start a new report
    bst_report('Start', sFiles);
    
    % Process: Average: Everything
    sFiles = bst_process('CallProcess', 'process_average', sFiles, [], ...
        'avgtype',         1, ...  % Everything
        'avg_func',        1, ...  % Arithmetic average:  mean(x)
        'weighted',        0, ...
        'scalenormalized', 0);
   
    % Process: Add tag: baseline
    sFiles = bst_process('CallProcess', 'process_add_tag', sFiles, [], ...
        'tag',           char(conditions(ii)), ...
        'output',        1);  % Add to file name

    sFiles = bst_process('CallProcess', 'process_add_tag', sFiles, [], ...
        'tag',          char(conditions(ii)), ...
        'output',        2);  % Add to file path
          
    % Save and display report
    ReportFile = bst_report('Save', sFiles);
    bst_report('Open', ReportFile);
    % bst_report('Export', ReportFile, ExportDir);
    % bst_report('Email', ReportFile, username, to, subject, isFullReport);
    
    % Delete temporary files
    % gui_brainstorm('EmptyTempFolder');
end

The error--

Dot indexing is not supported for variables of this type.

Error in bst_process>Run (line 285)
        allStudies = bst_get('Study', unique([sInputs.iStudy]));

Error in bst_process>CallProcess (line 2314)
        OutputFiles = Run(sProcess, sInputs, sInputs2, 0);

Error in bst_process (line 38)
eval(macro_method);

The following is a picture to help with the structure of the data:

The following is a ss of the error that I get when I try open the output file: