Run CFront

Hello,

I have trouble to test CFront. I would like connect to database open company ...
But i have an error

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

Hangs on line front.ConnectServerAndOpenDatabase

Client version is 4.00 SP2 (5.0 SP1)

           NavisionValue Data;

            String NavisionPath = "C:\\Program Files\\Microsoft Dynamics NAV\\CSIDE Client\\";
            CFrontDotNet front=new CFrontDotNet(NavisionDriverType.Sql,NavisionPath);

            int CT; // Currentt Table. Keep name short, since we need to type it in a lot

            int CR; // CurrentRecord. Keep name short, as above

           
            front.ConnectServerAndOpenDatabase("Navision", NavisionNetType.SqlDefault, "my_database", 2000, true, false,"demo", "demo");

            front.OpenCompany("Test company");

            CT = front.OpenTable(18);

            CR = front.AllocRecord(CT);

            front.FindFirstRecord(CT, CR);

            Data = front.GetFieldData(CT, CR, 2);

            NavisionText NAVText;

            NAVText = Data;

            textBox1.Text = NAVText.ToString();

            // Important: Close down Navision when finished.

            front.FreeRecord(CR);

            front.CloseTable(CT);

            front.CloseCompany();

            front.CloseDatabase();

            front.DisconnectServer();

            front.Dispose();

Any sugestion are welcome.
Thank you