USPS Shipping module URLs - Where to enter them?

I have not been able to get the USPS shipping module to work and I was wondering if anyone has an advice. USPS sent me several URLS to the production server, but I am not sure where they should be entered. Here is the email they sent me:

Thank you for contacting us. Congratulations on completing your testing using the U.S. Postal Service's Internet Shipping Application Program Interfaces (APIs).
Your profile has been updated to allow you access to the Production Server.

1. The Production Server URL is: http://production.shippingapis.com. For APIs calling the secure server, the URL is https://secure.shippingapis.com.
2. There is a line of code that refers to "shippingapitest.dll". You'll need to remove the word "test".

If you are using third party software and need assistance, please contact the vendor of the software. They should be able to assist you in obtaining live information using our APIs.

I am using version 1.2.7 of Zen Cart...which files do I add this info too?

Thanks!

You need a valid USPS shipping module ... look in the Security Patches and Updates for a link:
http://www.zen-cart.com/forum/showthread.php?t=131115

Make sure that you have called USPS and had them enable your account for the Production Server ...

NOTE: we are on v1.3.9c and you should really look at upgrading your shop to the current version as there are many bugs, security issues and lack of features in that ancient version that you are using ...

I followed the instructions for insalling the new 2010 USPS module and it just doesn'twork on my version 1.2.7. On line 16 when you include class usps extends base { you get a store error, when you change it to ```
class usps {

What is the exact error that you get ... I cannot reproduce any errors changing that line ... :unsure: