Gateway Error Message

Hello,

I’ve installed the authorize.net gateway in the Responsive shop Theme and set it up and processed a sale. The transaction went through fine and my credit card was charged and the merchant account paid. I received an approved transaction confirmation email from authorize.net as the purchaser and one to the merchant confirming same. So all works fine there. However, three problems:

1. After the transaction processes I got this error message from authorize.net in my browser instead of a thank you page:

An error occurred while trying to report this transaction to the merchant. An e-mail has been sent to the merchant informing them of the error. The following is the result of the attempt to charge your credit card.

This transaction has been approved.

It is advisable for you to contact the merchant to verify that you will receive the product or service.

2. There is no product detail in either or the emails from authorize.net (no invoice information)

3. The Website did not send any confirm order emails although I set one up for the user and one for admin.

Perhaps I forgot something in the set-up? How so I fix this?

Thank you!