Error when using multiple threads (c#)

using System;



using System.Threading;



using sfFTPLib;







namespace FTPExample



{



    class Program



    {



        static void Main(string[] args)



        {







            //create a new thread



            Thread ftpThread = new Thread(new ThreadStart(CheckFTPSite));



            ftpThread.Name = "ftp_check";



            ftpThread.TrySetApartmentState(ApartmentState.MTA);



            ftpThread.Start();







            Console.WriteLine("Press 'q' to quit.");



            while (Console.Read() != 'q');



        }







        private static void CheckFTPSite()



        {



            FTPLib objFTP = new FTPLib("ftp.test.com", "test", "test", 21);



        }



    }







    class FTPLib



    {



        public FTPLib(string url, string username, string password, int port)



        {







            FTPConnectionMTA _ftp = new FTPConnectionMTA(); //the application will hang after this line.







            // host settings



            _ftp.Host = url;



            _ftp.Port = port;



            _ftp.Username = username;



            _ftp.Password = password;



            _ftp.Passive = true;







            // proxy settings



            _ftp.ProxyType = sfFTPLib.enumProxyType.ftpProxyTypeNone;



            _ftp.FTPProxyType = sfFTPLib.enumFTPProxyType.ftpFTPProxyTypeNone;







            // set CLNT name



            _ftp.Client = "test app";



            // log everything 



            _ftp.LogFile = "WorkingProgressSFM.log";











        }



    }



}