Stuck in Step 1, using USPS

Hello, my client's ZenCart is stuck on Step 1 of the checkout process.
This problem was present before I upgraded the USPS module, but from what I have reaad in other discussions the Step 1 loop is related to the shipping module.

Only USPS is used for shipping and here are the settings:

Enable USPS Shipping
True

Enter the USPS Web Tools User ID
268STRYK1507

Which server to use
production

Handling Fee - US
0

Handling Fee - International
0

Handling Per Order or Per Box
Box

Percent Shipping Discount
0

Quote Sort Order
Unsorted

Tax Class
Taxable Goods

Tax Basis
Billing

Shipping Zone
--none--

Sort Order
0

All Packages are Machinable
False

International Quote Options
--none--

Domestic Quote Options
--none--

USPS Options
Display weight, Display transit time

Package Dimensions Config
regular;+

Enable Commercial Shipping
N

Domestic Shipping - Commercial Services
--none--

Domestic Shipping Methods
Express Mail, Priority Mail, First-Class Mail Package, Media Mail

International Shipping Methods
Global Express, Express Mail Int, Priority Mail International, First Class Mail Int Package

Shipping Quote Options Filtering
Off

Debug Mode is showing:

USPS Debug Mode Enabled!
weight: +lb, dimensions: regular Setting dimensions: l=12 w=12 h=12 for Weight: 11.2

Any suggestions will be very much appreciated.

Thank you.