Paypal return to Merchant, asking to authenticate

After a customer makes a purchase in Paypal standard on my Zencart store, hosted in Godaddy, the return to merchants icon takes them to a page with only two blank fields (such as a username and password) and a button that says "authenticate." Funny thing is that the transaction shows up an Zencart and the customer is able to log on for the download. I sell an eBook online and the customer needs to get back to Zencart from Paypal to download it. Any help would be appreciated.

Using 1.3.8a

That's not the way it normally works.

It sounds like you've got some sort of protected directory setup up and it's returning there for some reason instead of going back to the end of checkout like Zen Cart normally does when returning from PayPal.

Thanks Doc for getting back to me so quick. The domain that I'm using is a subdomain with godaddy. Would that have anything to do with it?