vb.net - Send File Via Ftp Using VB.Net In .Net 2003

Question

I want to send the file via FTP on server using vb.net(Vs 2003,framework 1.1) is throwing an exception

AN EXCEPTION OCCURED DURING THE WEBCLIENT REQUEST

The same code is working fine in .Net 2008. I have no Idea why its throwing the exception.

Imports System.Data.SqlClient
Imports System.Text
Imports Microsoft.VisualBasic
Imports System.Net.WebRequest
Imports System.Net.WebClient
Imports System.Net
Imports System.IO


If (Directory.Exists(directoryPath)) Then
    arrFileList = Directory.GetFiles(directoryPath) '''Getting All files 
Else
    MessageBox.Show("Directory not Exist")
End If

    For i As Integer = 0 To i < arrFileList.Length - 1

            Try
                Dim fileName As String = arrFileList.GetValue(i)
                Dim toUpload As New FileInfo(fileName)
                Dim client As New WebClient

                Dim nc As New NetworkCredential("xxxx", "xxxx") 

                Dim addy As Uri
                addy = New Uri("ftp://1xx.xx.xxx.xxx/HYPOSII_FTP/Test/" & toUpload.Name.ToString())               


                client.Credentials = nc
                Dim arrReturn As Byte() = client.UploadFile(addy.ToString(), fileName) //This Line Throwing error
                MessageBox.Show("File Uploaded Sucessfully")
                FLAG = True                
            Catch ex As Exception
                MessageBox.Show(ex.Message)
            End Try
        Next