553 error in ftp server

Dim createFTP As String = Convert.ToString(host & Convert.ToString("/")) & remoteFile
' Create an FTP Request 
ftpRequest = DirectCast(FtpWebRequest.Create(createFTP), FtpWebRequest)

' Log in to the FTP Server with the User Name and Password Provided 
ftpRequest.Credentials = New NetworkCredential(user, pass)
'ftpRequest.Credentials = New NetworkCredential(user, pass, createFTP)

' When in doubt, use these options 
ftpRequest.UseBinary = True
ftpRequest.UsePassive = True
ftpRequest.KeepAlive = True

' Specify the Type of FTP Request 
ftpRequest.Method = WebRequestMethods.Ftp.UploadFile

' Establish Return Communication with the FTP Server 
ftpRequest.Timeout = 600000
ftpRequest.ReadWriteTimeout = 600000

' read in file...
Dim bFile() As Byte = System.IO.File.ReadAllBytes(localFile)

'  ftpStream = ftpRequest.GetRequestStream()
' Open a File Stream to Read the File for Upload 
Dim clsStream As System.IO.Stream = ftpRequest.GetRequestStream()
clsStream.Write(bFile, 0, bFile.Length)
clsStream.Close()
clsStream.Dispose()

ftpRequest = Nothing
Catch ex As WebException
  MsgBox(ex.ToString())
End Try