I am working in a publishing site and wanted to create a site template
based on a subsite.
1. I see no link in the site settings for "save site as template" so I
append the url to /_layouts/savetmpl.aspx and am able to create the
site template.

2. Once the template is created, I try to create a site based on that
template, when the site creation screen is completed (the progress bar
page shown while the site is being created) I get this error:

This page is not using a valid page layout. To correct the problem,
edit page settings and select a valid page layout."

I append the url to the site settings page and attempt to change the
page layout settings, but nothing seems to make a difference.