Simple change to comment line 21: the=>that.
diff --git a/system/core/Controller.php b/system/core/Controller.php
index 92f7f17..c9d797c 100644
--- a/system/core/Controller.php
+++ b/system/core/Controller.php
@@ -18,7 +18,7 @@
 /**
  * CodeIgniter Application Controller Class
  *
- * This class object is the super class the every library in
+ * This class object is the super class that every library in
  * CodeIgniter will be assigned to.
  *
  * @package		CodeIgniter