diff -ur quiz_ei/results_export/results_export.admin.inc quiz_ei_new/results_export/results_export.admin.inc
--- quiz_ei/results_export/results_export.admin.inc	2010-08-03 23:17:40.425048804 +0200
+++ quiz_ei_new/results_export/results_export.admin.inc	2010-08-03 23:44:04.917566235 +0200
@@ -78,7 +78,8 @@
   $handle = @fopen($filepath, 'w');
   fwrite($handle, $output);
   fclose($handle);
-  $headers = array('Content-Type: text/html', 'Content-Disposition: attachment; filename='. $filename);
+  $ext = pathinfo($filename, PATHINFO_EXTENSION);
+  $headers = array('Content-Type: text/'. $ext, 'Content-Disposition: attachment; filename='. $filename);
   ob_clean();
   file_transfer($filepath, $headers);
   ob_end_clean();