Index: includes/theme.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/theme.inc,v
retrieving revision 1.607
diff -u -p -r1.607 theme.inc
--- includes/theme.inc	2 Sep 2010 15:58:53 -0000	1.607
+++ includes/theme.inc	4 Sep 2010 07:44:54 -0000
@@ -601,9 +601,10 @@ function list_themes($refresh = FALSE) {
     foreach ($themes as $theme) {
       foreach ($theme->info['stylesheets'] as $media => $stylesheets) {
         foreach ($stylesheets as $stylesheet => $path) {
-          $theme->stylesheets[$media][$stylesheet] = $path;
+          if (file_exists($path)) {
+            $theme->stylesheets[$media][$stylesheet] = $path;
+          }
         }
-      }
       foreach ($theme->info['scripts'] as $script => $path) {
         if (file_exists($path)) {
           $theme->scripts[$script] = $path;