diff --git a/_config.php b/_config.php
index eb5c24c..3b05107 100644
--- a/_config.php
+++ b/_config.php
@@ -26,4 +26,6 @@
  * consult the Commenting class.
  */
 
-Commenting::add('SiteTree');
\ No newline at end of file
+if(class_exists('SiteTree')) {
+	Commenting::add('SiteTree');
+}
\ No newline at end of file