--- ../original/includes/unicode.inc	Wed Nov 05 15:59:00 2008
+++ includes/unicode.inc	Tue Dec 09 22:35:06 2008
@@ -530,6 +530,11 @@ function drupal_substr($text, $start, $l
         $bytes--;
       }
     }
+    // length == 0
+    else {
+      $bytes = -1;
+    }
+    
     $iend = $bytes;
 
     return substr($text, $istart, max(0, $iend - $istart + 1));