Hey guys, I have an application that will display the last names, first names, and the first and last name in a listbox. Can anybody debug my code? It always crashes everytime I click the buttons.

Code:
 Private names(4) As PersonName

    Private Sub MainForm_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        ' fills array with data

        names(0).first = "Mary"
        names(0).last = "Jones"
        names(1).first = "Susan"
        names(1).last = "Washington"
        names(2).first = "Carol"
        names(2).last = "O'Brien"
        names(3).first = "Jacob"
        names(3).last = "Harper"
        names(4).first = "Sue"
        names(4).last = "Chen"
    End Sub

    Private Sub exitButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles exitButton.Click
        Me.Close()
    End Sub

    Private Sub lastButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles lastButton.Click
        ' displays the last names in a list box

        ' clear then list box, then display the last names
        namesListBox.Items.Clear()
        For row As Integer = 1 To names.Length
            namesListBox.Items.Add(names(row).last)
        Next row
    End Sub

    Private Sub firstButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles firstButton.Click
        ' displays the first names in a list box

        ' clear the list box, then display the first names
        namesListBox.Items.Clear()
        For row As Integer = 1 To names.Length
            namesListBox.Items.Add(names(row).first)
        Next row
    End Sub

    Private Sub fullButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles fullButton.Click
        ' displays the first and last names in a list box

        ' clear the list box, then display the first and last names
        namesListBox.Items.Clear()
        For row As Integer = 1 To names.Length
            namesListBox.Items.Add(names(row).first _
            & " " & names(row).last)
        Next row
    End Sub