In looking at the admin panel and the shipping modules page, I noticed the error message:
ERROR: module not loaded due to missing language file:/includes/languages/english/modules/shipping/usps_xx.php

At some point I had renamed the usps.php file to usps_xx.php, as a way to make a copy. Somehow, Zen now thinks that the file is called usps_xx. I'm at a loss to understand how this has happened. I'm sure it is something I did some time ago.
Its may be unrelated to this issue, I'm not sure.

The webservices module does not appear to have a version number. But I believe it is 1.3.2