[RESOLVED] Radio box

[brue]

I'm having a bit of a problem in a VB script. The assignment is the following: Get a form filled in with pressing 1 button.
In this form I can get everything correct, except for the radiobutton. As html sais, the first option is selected by default. Now when you press a button, ghi should get checked.

The html of this radiobox is the following:

<input type="radio" class="radio" name="c" value="2" checked="checked">abc
<br>
<input type="radio" class="radio" name="c" value="3">def
<br>
<input type="radio" class="radio" name="c" value="4">ghi

I saw this topic which sais, and made a bit of my own variant to this:

Public Class Form1
    Private Function GetCurrentWebDoc() As mshtml.HTMLDocument
        Try
            Return DirectCast(WebBrowser1.Document, mshtml.HTMLDocument)
        Catch ex As Exception
            Return Nothing
        End Try
    End Function

    'SAME AS THE ABOVE FUNCTION, EXCEPT IT GRABS A WEBFORM. I ASSUME HERE THERE IS ONLY 1 FORM
    'IF YOU WERE DEALING WITH A PAGE WITH MULTIPLE FORMS, SIMPLY USE ITS INDEX (THEY ARE IN AN ARRAY)
    'THIS IS A USEFUL METHOD BECAUSE OFTEN TIMES WHEN MANIPULATING A WEBPAGE, ITS TO GET/SET DATA IN A FORM
    Private Function GetCurrentWebForm() As mshtml.HTMLFormElement
        Try
            If GetCurrentWebDoc.forms.length > 0 Then
                Return DirectCast(GetCurrentWebDoc.forms.item(0), mshtml.HTMLFormElement)
            Else
                Return Nothing
            End If
        Catch ex As Exception
            Return Nothing
        End Try
    End Function
    'SET THE RADIO BUTTONS CHECKED. NOTICE THEY ARE BOTH CALLED THE SAME THING, BUT THE INDEX IS DIFFERENT.
    Private Sub SetRadioYesChecked()
        If x.Checked Then
            DirectCast(GetCurrentWebForm.item("c", 3), mshtml.HTMLOptionButtonElement).checked = True
        Else
            DirectCast(GetCurrentWebForm.item("c", 4), mshtml.HTMLOptionButtonElement).checked = True
        End If
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Select Case True

            Case x.Checked, y.Checked : SetRadioYesChecked()

        End Select

    End Sub
End Class

in this project I have 2 radiobuttons, a webbrowser(which has the html), and a button. When the 1st option(in application) is selected and the button is pressed it should select the 2nd option(in browser), if the 2nd option(in application) is selected, and the button gets pressed it should select the 3rd option(in browser). But when I press the button it sais: 'Object reference not set to an instance of an object.' So why did it work at the other application, but why won't it work with mine?

I'm not asking for a ready script I can copy and paste, just some hints so I can solve it myself. It's a assignment, so I should learn something from it

I'm using visual studio if this might make a difference.

Greetings,
Ray