Code:
Public Class Form1


    Dim int As Integer = 0
    Dim CustomerTable As New DataTable
    Dim instance As New InvalidOperationException()

    Class TestClass
        Public field1 As Integer
        Dim field2 As Boolean
    End Class




    Private Sub Loading(ByVal sender As Object, ByVal e As Windows.Forms.WebBrowserProgressChangedEventArgs)
        ToolStripProgressBar1.Maximum = e.MaximumProgress
        ToolStripProgressBar1.Value = e.CurrentProgress
    End Sub
    Private Sub Done(ByVal sender As Object, ByVal e As Windows.Forms.WebBrowserDocumentCompletedEventArgs)

        TabControl1.SelectedTab.Text = CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).DocumentTitle
        ToolStripComboBox1.Text = CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Url.ToString


    End Sub
    Private Sub ToolStripButton1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton1.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).GoBack()
    End Sub

    Private Sub ToolStripButton2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton2.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).GoForward()
    End Sub

    Private Sub ToolStripButton3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton3.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Refresh()
    End Sub

    Private Sub ToolStripButton4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton4.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).GoHome()

    End Sub

    Private Sub ToolStripButton5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton5.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Navigate(ToolStripComboBox1.Text)
    End Sub
    Private Sub ToolStripButton6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton6.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).GoSearch()
    End Sub

    Private Sub PageProprietysToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PageProprietysToolStripMenuItem.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).ShowPropertiesDialog()

    End Sub
    Private Sub ToolStripButton10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton10.Click
        Dim Browser As New WebBrowser
        TabControl1.TabPages.Add("New Page")
        TabControl1.SelectTab(int)
        Browser.Name = "FireWolf"
        Browser.Dock = DockStyle.Fill
        TabControl1.SelectedTab.Controls.Add(Browser)
        AddHandler Browser.ProgressChanged, AddressOf Loading
        AddHandler Browser.DocumentCompleted, AddressOf Done

        int = int + 1
    End Sub







    Private Sub PasteToolStripButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PasteToolStripButton.Click
        If Not TabControl1.TabPages.Count = 1 Then
        End If
        TabControl1.TabPages.RemoveAt(TabControl1.SelectedIndex)
        TabControl1.SelectTab(TabControl1.TabPages.Count - 1)
        int = int - 1
    End Sub

    Private Sub ToolStripButton9_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton9.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Navigate("www.youtube.com")
    End Sub

    Private Sub ToolStripButton8_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton8.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Navigate("www.yahoo.com")
    End Sub

    Private Sub ToolStripButton7_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton7.Click
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Navigate("www.google.com")
    End Sub

    Private Sub ToolStripComboBox1_keydown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles ToolStripComboBox1.KeyDown
        If e.KeyCode = Keys.Enter Then
            ToolStripComboBox1.Items.Add(ToolStripComboBox1.Text)
            CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Navigate(ToolStripComboBox1.Text)
            Me.Text = (ToolStripComboBox1.Text)

        End If
    End Sub
    Private Sub ToolstripCombobox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripComboBox1.SelectedIndexChanged
        CType(TabControl1.SelectedTab.Controls.Item(0), WebBrowser).Navigate(ToolStripComboBox1.Text)
    End Sub

End Class
This is the code this exception occurs when i click on the home button of my webbrowser.
Or i enter any site on the combobox.