I had the same problem, and I think it's simply likely to mean that civicrm is not installed in your new site. I solved the problem by re-running
civibuild destroy mysitename
civibuild create mysitename --url http://localhost:8080
My initial install command contained an error which explains why civicrm was not downloaded/installed successfully. Short of doing a manual civicrm install via the CRMCMS, there didn't seem an obvious way to fix a missing component from the buildkit install.
If you're using docker, I think you need to prepend 'docker-compose exec -u buildkit civicrm' to those commands, or login to the docker container.