Поправил namespace

src/Model/Factory.php

@@ -8,7 +8,6 @@ class Factory
     static $shortcut = "model";
     public $db;
     public $_registry;
-    public $_shortcut;
 
     public function __construct (/*.Database.*/ $db, Settings $_registry = null)
     {
@@ -23,7 +22,7 @@ class Factory
      */
     public function getModel ($name)
     {
-        $modelName = "Mapper_" . $name;
+        $modelName = "App\\Mapper\\" . $name;
         $model = new $modelName();
         $model->db = $this->db;
         $model->factory = $this;