Index: application.php
===================================================================
--- application.php	(revision 15457)
+++ application.php	(working copy)
@@ -1224,7 +1224,11 @@
 
 		// flush all output
 		ob_end_flush();
-		ob_flush();
+
+		if ( ob_get_level() ) {
+			ob_flush();
+		}
+
 		flush();
 
 		// close current session