I have the shipping methods checked. BUT....now when I go to usps and hit the edit button, I completely lose the right column so I can't even edit it. We were getting closer to the problem too.
Do I need to put my zipcode into the php file and do you have a line number? It was working but this was the current message. Before I lost the ability to edit.

United States Postal Service United States Postal Service
We are unable to find a USPS shipping quote suitable for your mailing address and the shipping methods we typically use.
If you prefer to use USPS as your shipping method, please contact us for assistance.
(Please check that your Zip Code is entered correctly.)