Подключение к базе данных

[veter48]

Здравствуйте, пытаюсь подключится к локальной базе данных:

            string CommandText = "SELECT Klienta ID, Uzvards, Vards FROM Klienti";
            string ConnectionString = @"Data Source = .\SQLEXPRESS;AttachDbFilename=" + '\u0022' +
                @"C:\Program Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\DATA\Clients.mdf" + '\u0022' +
                ";Integrated Security = True; Connect Timeout = 30; User Instance = True";
            SqlDataAdapter dataAdapter = new SqlDataAdapter(CommandText, ConnectionString);
            DataSet ds = new DataSet();
            dataAdapter.Fill(ds, "Klienti");

При dataAdapter.Fill(ds, "Klienti"); вылетает ошибка :

Unable to open the physical file "C:\Program Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\DAT A\Clients.mdf". Operating system error 32: "32(failed to retrieve text for this error. Reason: 15105)".
An attempt to attach an auto-named database for file C:\Program Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\DAT A\Clients.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.

В чем проблема? Спасибо.