Reload Browser using List Items

Dear friends,

I have a developed a browser app with VB 2010.

In the ListBox, I have a list of urls that each will auto load after 15sec using the Timer_Tick method.

If the urls in the ListBox are exhausted, the IndexVariable should restart from the 1st Index of the ListBox Items - i.e, there should be a loop until StopButton_clicked event is called.

Pls check the following Code:

'this is a Module Class Variable declared as Public
Public indexValue As Integer = 0
'The Timer.Interval value = 15000ms = 15sec
'the is the Start Timer Button Event
Private Sub startTime_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles startTime.Click
        LoadTime.Start()
        lblCount.Text = ""
        ToolStripStatusLabel1.Text = "Timer Started..."
    End Sub
'this is the Timer_Tick event
 Private Sub LoadTime_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles LoadTime.Tick
        WebPageBrowser.Navigate(conv_urls.Items(indexValue)) 'this is where the error occurs... as
' InvalidArgument=Value of '3' is not valid for 'index'. Parameter name: index'
'Note that there are only 3 items in the ListBox...
        '
        '     Increment the shared variable
        '
        indexValue = indexValue + 1 'But I want the system to loop from beginning.
        'here, conv_urls is a ListBox control
        If indexValue > conv_urls.Items.Count Then
            indexValue = 0
            LoadTime.Interval = 0
            'LoadTime.Stop()
        End If
        'Loop
    End Sub
'this is the Stop Timer Button Event
 Private Sub StopBut_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles StopBut.Click
        If LoadTime.Interval = 15000 Then
            Exit Sub
        Else
            WebPageBrowser.Stop() 'this is the WebBrowser Control
            LoadTime.Stop()
            indexValue = 0
            LoadTime.Interval = 0
            ToolStripStatusLabel1.Text = "Timer Stopped!"
        End If

    End Sub

Please help me.
Thank you!

Eyo Honesty