Error: Specify Roles During Registration

Hi 2 all,
I want to create a user wizard from which the user can choose the roles during the registration procedure..
For this i followed a video tutorial and wrote the following code


<script runat="server">
    Public Sub ActivateStep(ByVal sender As Object, ByVal e As System.EventArgs)
        ListBox1.DataSource = Roles.GetAllRoles()
        ListBox1.DataBind()
    End Sub
    
    Public Sub DeactivateStep(ByVal sender As Object, ByVal e As System.EventArgs)
        Roles.AddUsersToRole(New [String]() {User.Identity.Name}, ListBox1.SelectedValue)
    End Sub

    
</script>


    <asp:CreateUserWizard ID="CreateUserWizard1" runat="ser ...