Property;RegForm.password2;is not defined. [ 新手入门 ]

<?php
class IndexController extends Controller
{
    public function actionIndex()
    {
        $this->render("index");
    }	
	
    public function actionReg()
    {
        $model=new RegForm;  
        if(isset($_POST['RegForm']))
        {
            // 收集用户输入的数据
            $model->attributes=$_POST['RegForm'];
            echo "dfs";
            // 验证用户输入，并在判断输入正确后重定向到前一页
            if($model->validate())
                $this->redirect(Yii::app()->user->returnUrl);
        }
		$this->render("reg",array('model'=>$model));
	}
	
	public function actionCheck()
	{
            if(isset($_POST['RegForm']))
	    {
	        // 收集用户输入的数据
	        $model->attributes=$_POST['RegForm'];
	        echo "dfs";
	        // 验证用户输入，并在判断输入正确后重定向到前一页
	        if($model->validate())
	            $this->redirect(Yii::app()->user->returnUrl);
	    }
	}

}
<?php 
class RegForm extends CFormModel
{
    public $username;
    public $password;
    public $rememberMe=false;
 
    private $_identity;
 
    public function rules()
    {
        return array(
            // username and password are required
            array('username, password', 'required'),
            array('username','length','min'=>3,'max'=>12),
            array('password','length','min'=>6,'max'=>16),
            array('password','compare','compareAttribute'=>'password2'),
            //array('email','email'),
            array('rememberMe', 'boolean'),
        );
    }
 
    public function authenticate($attribute,$params)
    {
        $this->_identity=new UserIdentity($this->username,$this->password);
        if(!$this->_identity->authenticate())
        {
            $this->adderror('username','必须输入用户，且长度为3位');
            $this->adderror('username','必须输入用户，且长度为3-12位');
            $this->addError('password','必须输入密码，且长度为6-16位');
            $this->addError('password','密码不相等');
            
        }
    }
}
?>
<div class="form">
<?php echo CHtml::beginForm($action='reg',$method='post',$htmlOptions=array('name'=>'RegForm')); ?>
<?php echo CHtml::errorSummary($model); ?>
<div class="row">
    <?php echo CHtml::activeLabel($model,'username'); ?>
    <?php echo CHtml::activeTextField($model,'username') ?>
</div>
 
<div class="row">
    <?php echo CHtml::activeLabel($model,'password'); ?>
    <?php echo CHtml::activePasswordField($model,'password') ?>
        
</div>
<div class='row'>
    <?php echo CHtml::activeLabel($model,'password2'); ?>
    <?php echo CHtml::activePasswordField($model,'password2') ?>
</div>
<div class="row rememberMe">
    <?php echo CHtml::activeCheckBox($model,'rememberMe'); ?>
    <?php echo CHtml::activeLabel($model,'rememberMe'); ?>
</div>
 
<div class="row submit">
    <?php echo CHtml::submitButton('注册'); ?>
</div>
 
<?php echo CHtml::endForm(); ?>
</div><!-- form -->