f you receive a "Code 04" error when trying to set up an account for online processing of a certain credit card type, this means that your merchant account isn't properly set up for that card type in the First Data database. When you add a payment processor Yahoo! automatically tests which payment options your account is set up to use. Those payment options will be displayed in your checkout pages and associated with the correct payment processor
To resolve a "Code 04" error, you need to contact your merchant account provider to make sure they have set up your account in the First Data database for that card type.
You will not be able to associate a payment option such as Visa or MasterCard with a payment processor that is not set up to process that card type. After contacting your payment processor directly and adding new card types to your account, you can then associate the new card types with your processor. From the Store Manager, click the Payment Center link. Click the Payment Options button and then click the link in the Payment Processor column for the card type you wish to associate. A dialog box will appear from which you can select your payment processor.