diff --git a/install/lib/installer_base.lib.php b/install/lib/installer_base.lib.php
index 3c718a91b8f8cdbed3996b49f45e6df9d8c2388e..3f3caaaa567080ebdf9260e04c2daa78ff6199d8 100644
--- a/install/lib/installer_base.lib.php
+++ b/install/lib/installer_base.lib.php
@@ -34,7 +34,7 @@ class installer_base {
 	var $language = 'en';
 	var $db;
 	public $conf;
-	public install_ispconfig_interface = true;
+	public $install_ispconfig_interface = true;
 
 
     public function __construct()