When installing the SUPEE-7405 on magento 1.7.0.0 the patch is trying to remove the comment on these lines:
-/* @var $_helper Mage_Authorizenet_Helper_Data */ -$_helper = $this->helper('authorizenet'); +/* @var $_helper Mage_Authorizenet_Helper_Admin */ +$_helper = $this->helper('authorizenet/admin');
However the comment
@var $_helper Mage_Authorizenet_Helper_Data
was not added until magento 1.7.0.1 and not in 1.7.0.0
I have got around the issue by added the comment to the file and then running the patch.
Hi @rob3000, were you able to get this working?
I needed to add
/* @var $_helper Mage_Authorizenet_Helper_Data */
above the helper declaration comment to the file and then ran the patch again and it worked.