If you get an SQL error when trying to save the Viewer template such as “Server internal error. Error logged with id xx. You have an error in your SQL syntax”, and the modified Viewer email template has not taken effect, then you have attempted to update the Viewer template in the wrong location.
You MUST modify the Viewer email template from your Publisher Account and NOT from the Master Admin > Settings Tab.
From the Master Admin, go to the Publishers Tab, press the Details button on your Publisher account and then select the Custom Template radio button in the section ‘Publisher PDF Viewer Registration email template’.