如何重定向辅助类内部

In Magento, I have a helper class data

class My_Advert_Helper_Data extends Mage_Core_Helper_Abstract {

where

I have a function such as

    public function callValid($arrError){
.....

and in that function I am trying to redirect user to a certain login...

$this->_redirect($strReturnPath);

The setUrl is not redirecting. How can I redirect?.. $strReturnPath is getting */ as path. I need it to go to homepage Receiving error like below

Fatal error: Call to undefined method My_Advert_Helper_Data::_redirect() in 

You can set redirects within your helper class like the following

 Mage::app()->getResponse()->setRedirect($strReturnPath);

That should do the trick.