diff --git a/lib/SimpleSAML/Error/Error.php b/lib/SimpleSAML/Error/Error.php
index 7689d5f7525993096c49c981688559736db86e30..542c35be43124a6e335092e5d5b3473c3f873359 100644
--- a/lib/SimpleSAML/Error/Error.php
+++ b/lib/SimpleSAML/Error/Error.php
@@ -44,9 +44,9 @@ class SimpleSAML_Error_Error extends SimpleSAML_Error_Exception
 
 
     /**
-     * The name of module which throw error.
+     * The name of module that threw the error.
      *
-     * @var string|NULL
+     * @var string|null
      */
     private $module = null;
 
@@ -62,7 +62,7 @@ class SimpleSAML_Error_Error extends SimpleSAML_Error_Exception
     /**
      * Name of custom include template for the error.
      *
-     * @var string|NULL
+     * @var string|null
      */
     protected $includeTemplate = null;