this point to a problem in the Dreamweaver site settings, specifically the URL Prefix used in the Testing Server section.
It looks you entered 127.0.0.1 as the URL prefix, what happens if you open a web browser and paste that address in the address bar?
What operating system are you using?
Have you installed a testing server?
See the learning resources page for details on installing a testing server:
this page will will also have tutorials for configuring the Site in Dreamweaver and creating the database connection.