This contribution is really a fix/work around for the "Shopping Cart Empty" bug that had been reported by a number of osCommerce developers and users.
After much researching osCommerce forums, bug reports, Google, etc. I could not find a satisfactory answer to the empty cart bug. Although there were a number of good suggestions regarding hosting on a secure server or not, changing the config file settings for the cookie path, turning on various session options, changing session storage to mysql or the file system - none had any affect on the outcome of an empty cart whenever a customer choose to add the product to their cart.
My work around involves a slight change to the product_info.php module.