html agility pack ~ how can I get all inputs of a form~ error code given

Imports System.Net
Imports System.IO
Imports System.Text


Imports HtmlAgilityPack

Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        HtmlNode.ElementsFlags.Remove("form")
        Dim doc As New HtmlDocument()
        doc.LoadHtml("http://mywebsiteishere/")
        Dim secondForm As HtmlNode = doc.GetElementbyId("form2")
        For Each node As HtmlNode In secondForm.Elements("input")
            Dim valueAttribute As HtmlAttribute = node.Attributes("value")
            If valueAttribute IsNot Nothing Then
                Console.WriteLine(valueAttribute.Value)
            End If
        Next





    End Sub
End Class