Adding product to registry

[Guest]

I have the registry contribution plugged into my store. When I create a registry and attempt to add product to my registry, the product isnt being added to the database. For example, I create a registry and go to add a mattress to my gift registry. When I hit the add to registry button, the registry_products.php pages says, "Your Gift Registry is empty!". I go check my database and the product isnt there. Can anyone tell me where the sql is that adds this product. What file is processed between the product_info.php page and the registry_products.php page? Thanks in advance for your help!