My Ftp Program works only on the host machine and not from a remote machine

 Guys,
I have written an ftp program using the code from the video turorials. This code works perfectly when debugged and tested on the development (host) machine - when both the application and the server are on the same machine. The login is anonymous. The application does not transfer files to the remote server when tested from a different machine. Any ideas? This is my code:
Try

  'Get FTP web resquest object.
  ftpWR = CType(FtpWebRequest.Create(New Uri("ftp://" + System.Configuration.ConfigurationManager.AppSettings("ftpServer").ToString() + "/" + uploadFile.FileName)), FtpWebRequest)
  ftpWR.UseBinary = True
  ftpWR.Method = WebRequestMethods.Ftp.UploadFile
  ftpWR.Credentials = New NetworkCredential(System.Configuration.ConfigurationManager.AppSettings("ftpUserName").ToString(), System.Configuration.ConfigurationManager.AppSettings("ftpPassw ...