When deleting an enterprise project using the Delete Enterprise Objects page in PWA, the Project Server administrator has the option to delete the Project Workspace (knwon as the Project Site in Project Server 2010) associated with the project. If the Project Server administrator fails to delete the Project Workspace, then this results in an "orphaned" Project Workspace that is not associated with any enterprise project.
Resolution for Project Server 2007 and 2010
To delete an orphaned Project Workspace (Project Site), the Project Server administrator must complete the following steps:
1. Log into Project Web Access with administrator permissions.
2. Click the Site Actions pick list and select the Site Settings item on the menu.
3. Click the "Sites and workspaces" link in the Site Administration section of the page.
4. On the Sites and Workspaces page, click the Delete icon (X) for the Project Workspace you want to delete.
5. On the Delete This Site page, click the Delete button.
6. Click the OK button to confirm the deletion.