Index: simplemenu/simplemenu.module
===================================================================
--- simplemenu/simplemenu.module	(revision 5626)
+++ simplemenu/simplemenu.module	(working copy)
@@ -132,7 +132,7 @@
     // XXX add a variable simplemenu_update which is set to TRUE whenever
     //     the settings get modified and false here
     $output_filename = variable_get('simplemenu_css_filename', '');
-    if (!$output_filename) {
+    if (!$output_filename || !file_exists($output_filename)) {
       $tags = array(
         '@MENUBAR_ZINDEX@' => simplemnu_get_zindex('simplemenu_menubar_zindex', 9999),
         '@DROPDOWN_ZINDEX@' => simplemnu_get_zindex('simplemenu_dropdown_zindex', 9999),