Cannot start your application. The workgroup information file is missing or opened exclusively by another user. (Error 3028)

To ensure referential integrity in databases created by the Microsoft Jet database engine, your application must read the Microsoftｮ Jet database's System.mdw file. Make sure the file is in the location specified in the SystemDB value of the \HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\9.0\Access\Jet\4.0\Engines\Jet key in the Windows Registry.