Yii 框架表单提交按钮显示错误

我在尝试访问网址http://localhost/happybox/index.php/site/cart/3时Fatal error: Call to a member function hasErrors() on a non-object in F:'xampp'yii'framework'web'helpers'CHtml.php on line 2253
收到错误
。我的查看文件购物车的代码.php是：

Hello, <?php echo ucwords(Yii::app()->user->name); ?>,<br/>
This is your cart<br/>
Click on Order to Place and Order.<br/>
<?php 
$Orders = Orders::model()->findAll(array(
    'select'=>'products_id',
    'condition'=>'users_id=:id && type=:type',
    'params'=>array(':id'=>Yii::app()->user->id, ':type'=>'cart'),
));
?>
<?php 
if($Orders){
    foreach ($Orders as $order) {
    echo '<br/>'.$order->products->title.'<br/>'.$order->products->description.'<br/>';
    }
}else{
    echo 'Your Cart is Empty';
}
?><br/><br/>
<?php 
if($Orders){
   $form=$this->beginWidget('CActiveForm', array('id'=>'order-form')); 
   echo $form->hiddenField($model,'users_id',array('value'=>Yii::app()->user->id)); 
   echo CHtml::submitButton('Confirm Your Order'); 
   $this->endWidget(); 
}
?>

我的控制器函数的代码是

public function actionCart($id){
    if(Yii::app()->user->isGuest){
        $this->redirect('login');
    }else{
        $model=$this->loadModel($id);
        if(isset($_POST['Orders']))
        {        
        //do something
        }
        $this->render('cart', array('model'=>$model));
    }
}

有人可以指出此代码中的错误吗，这对我来说非常重要。请帮忙。