There are at least two other threads with solution on this issue and I followed them:
and they suggest to locate the troublesome site and delete it or create another instance using backup of the DBs.
I located the site and using the SharePoint Powershell I could resume the issue in the following phrase:
"System.IO.FileNotFoundException: The site Microsoft.Office.Project.Server.Administration.Project.Site could not be found."
I can access and navigate at the PWA site settings and at the SharePoint Central Administration. According to the second thread, should I delete this entry?
Any help is welcome.
Thank you.
Best regards, Ricardo Segawa - Segawas Projetos / Microsoft Partner