When I load my layout I catch exception. My layout :

<?xml version="1.0"?> <layout version="0.1.0"> <agentdeposit_success_success>         <reference name="head">             <action method="addItem"><type>skin_js</type><name>js/finalizeorder.js</name></action>         </reference>         <reference name="root">             <action method="setTemplate"><template>page/1column.phtml</template></action>         </reference>         <reference name="content">             <block type="agentdeposit/success" name="agentdeposit_success" template="agentdeposit/success_form.phtml" />         </reference>     </agentdeposit_success_success> </layout> 

My controller:

<?php class Payment_AgentDeposit_SuccessController extends Mage_Checkout_Controller_Action {      public function successAction()     {         $  this->loadLayout();         $  this->renderLayout();     } } 

and my block:

<?php class Payment_AgentDeposit_Block_Success extends Mage_Payment_Block_Form_Container {      protected $  _quote;      public function __construct()     {         parent::__construct();     }      public function _prepareLayout()     {         parent::_prepareLayout();         return $  this;     } } 

My exception on the photo. I broke my head. What it can be?