threads in vb.net 2005

dear..
I want to make program with threading (source I'm attached)
this program generate number (with timer) and save data in array.
if length of array is 100, the array will save in file. the contents
of array will replace with new number and generate again from beginning,
and so on.
this program right if I not use threading. but when I use threading,
output file is large. threading not stop when i use to try stop threading
after make file.
when I activated line
threadProgress.Name = "Background Thread"
threadProgress.IsBackground = True
this program is error.
can you help me ??

this is copy of my scripts

VB.NET Code:

Imports System.IO
Imports System.Math
 
Public Class Form1
    Public namaFile As String = "C:\sementara.txt"
    Public data1(100) As Double
    Public jumData As Short
    Private i As Short = 0
    Private k As Integer = 0
    Private threadProgress As System.Threading.Thread
    Dim InputNamaFile As StreamWriter
 
    Private Sub OkToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OkToolStripMenuItem.Click
        InputNamaFile = New StreamWriter(namaFile, False)
        jumData = 100
        InputNamaFile.Close()
        Timer1.Enabled = True
    End Sub
 
    Public Sub saveFile1()
        InputNamaFile = New StreamWriter(namaFile, True)
        Dim a As String
        For i = 0 To jumData - 1
            a = CStr(data1(i)) & ";" & CStr(data1(i))
            InputNamaFile.Write(a & vbNewLine)
        Next
        InputNamaFile.Close()
        OnFinished()
    End Sub
 
    Private Sub OnFinished()
        threadProgress = Nothing
    End Sub
 
    Private Sub ProcesDong1()
        threadProgress = New System.Threading.Thread(AddressOf saveFile1)
        'threadProgress.Name = "Background Thread"
        'threadProgress.IsBackground = True
        threadProgress.Start()
    End Sub
 
    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        Label1.Text = k
        data1(i) = k
 
        If i <= jumData - 1 Then
            data1(i) = k
        ElseIf i = jumData Then
            ProcesDong1()
            'saveFile1()
            i = -1
        End If
 
        If k = 210 Then
            Timer1.Enabled = False
        End If
 
        i = i + 1
        k = k + 1
    End Sub
End Class