Permission error while downloading file through IE8
Updated download_file module header.

 $headers = array(
   'Content-Type'              =&gt; 'force-download',
   'Content-Disposition'       =&gt; 'attachment; filename="' . $file-&gt;filename . '"',
   'Content-Length'            =&gt; $file-&gt;filesize,
   'Content-Transfer-Encoding' =&gt; 'binary',
   'Pragma'                    =&gt; 'private, no-cache',
   'Cache-Control'             =&gt; 'private, no-store, no-cache, max-age=0, must-revalidate',
   'Expires'                   =&gt; '0',
   'Accept-Ranges'             =&gt; 'bytes'
 );