OSCommerce Issue

Hi, The company I work for manages online products through the use of OSCommerce. One of our customers reported having the following message when trying to purchase on of the products:

Server Requirement Error: register_globals is disabled in your PHP configuration. This can be enabled in your php.ini configuration file or in the .htaccess file in your catalog directory.

I have no idea what to do, so any suggestions would be greatly appreciated.

Thanks in advance
Wisemas