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 08:26:11 -0000
@@ -164,7 +164,9 @@ function _drupal_theme_initialize($theme
   // And now add the stylesheets properly
   foreach ($final_stylesheets as $media => $stylesheets) {
     foreach ($stylesheets as $stylesheet) {
-      drupal_add_css($stylesheet, array('weight' => CSS_THEME, 'media' => $media, 'preprocess' => TRUE));
+      if (file_exists($stylesheet)) {
+        drupal_add_css($stylesheet, array('weight' => CSS_THEME, 'media' => $media, 'preprocess' => TRUE));
+      }
     }
   }