diff --git a/includes/common.inc b/includes/common.inc
index f80496b..a966c4d 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -3347,7 +3347,7 @@ function drupal_pre_render_styles($elements) {
             // drupal_load_stylesheet() checks file_exists(), but only when
             // building the aggregate file, which is then reused for many page
             // requests.
-            if (file_exists($item['data'])) {
+            if (file_exists(DRUPAL_ROOT . '/' . $item['data'])) {
               // The dummy query string needs to be added to the URL to control
               // browser-caching. IE7 does not support a media type on the
               // @import statement, so we instead specify the media for the