title: Add to cart button in osCommerce keeps redirecting back to product page
body: <p>I have an ebook item in osCommerce that includes product attributes. When I click the Add to Cart button from the index page it should go directly to the shopping_cart.php page. However, it only keeps redirecting the customer back to the product_info.php page.</p>
  
  <p>Why is it doing that?</p>