When trying to publish a project to Project Online you receive the following error:

The value for column ‘WSTS_SERVER_UID’ in table ‘EnterpriseProjectType’ is DBNull

This may occur if the project site is not yet created.  To fix, create the project site via the PWA before publishing.

Go to PWA Settings, under Operational Policies select ‘Connected SharePoint Sites’, select the Project you’re trying to publish and click ‘CREATE SITE’.  Once Active, try again to Publish.