If database was created manually by running the GPOADmin.sql script, then the InitializeDatabase stored procedure needs to be executed as well as stated in the
Quick Start Guide under
Minimum permissions required for the service accounts - To set up minimum permissions for the service accounts - step 5 - SQL step 2.If issue persists even after running the InitializeDatabase stored procedure, then delete the database and re-configure GPOADmin to use a new database name from within the product and let GPOADmin set up the new database to see if this corrects the issue. If the environment policies do not allow the creation of databases in this way, then have a DBA create a database giving the GPOADmin service account DBO rights on the database, then configure from within GPOADmin using the new database and let GPOADmin run the creation and initialization scripts from there. This reconfiguration could be done by right-click the domain in GPOADmin console, then click on Re-configure Version Control Server.