Start the Microsoft SQL Server Managment Studio Express
-Connect to Your DB
-Select: Security --> Logons/Logins(Anmeldungen)
-Doublecklick the Logon which is used by the TV-Server service (you told the server during the initial configuration)
-the pulldownbox "DefaultDB"(Standartdatenbank) should be "TVLibrary" if it is not change it to this value
after this modification you will have to restart the server and then it should work
excuse the labels I used, didn't manage to change the language of the MSSQLSMSE to English, so I had to improvise