You receive this error (Invalid Referrer, Relay Response, or Receipt Link URL) because you need to configure your receipt page URL.

Instructions

1. Log into the Authorize.net Merchant Interface
2. Click Account from the main toolbar
3. Click Response/Receipt URLs under Transaction Format Settings
4. Click Add URL
5. Enter your Response URL
6. Click Submit

Note: You can find the Default Relay Response URL on their site.