Urgent, Can't find code in checkout_payment.php

[electra]

I have aa box oscommerce im wondering if the catalog/checkout_payment.php on aabox is different from the original oscommerce catalog/checkout_payment.php, because im trying to find this code in the checkout_payment.php <link rel="stylesheet" type="text/css" href="stylesheet.css"> because i need to add some code below it to install this contribution but im looking and its no where in the code..Please help

[Guest]

Line 87 in my copy.