diff --git a/admin/admin_disallow.php b/admin/admin_disallow.php
index 6fe2ef3b..fdc1f23d 100644
--- a/admin/admin_disallow.php
+++ b/admin/admin_disallow.php
@@ -19,7 +19,7 @@ if (isset($_POST['add_name']))
 	{
 		bb_die($lang['FIELDS_EMPTY']);
 	}
-	if( !validate_username($disallowed_user) )
+	if( validate_username($disallowed_user) )
 	{
 		$message = $lang['DISALLOWED_ALREADY'];
 	}
diff --git a/library/includes/functions_selects.php b/library/includes/functions_selects.php
index e6fb9cec..5635cfbf 100644
--- a/library/includes/functions_selects.php
+++ b/library/includes/functions_selects.php
@@ -32,7 +32,7 @@ function tz_select ($default, $select_name = 'timezone')
 
 	if (!isset($default))
 	{
-		$default == $sys_timezone;
+		$default = $sys_timezone;
 	}
 	$tz_select = '<select name="' . $select_name . '">';