Can anyone help?  I getting this error on line 17:

Object reference not set to an instance of an object.

Line 15:         Dim UserGUID As Object = User.ProviderUserKey
Line 16:
Line 17:         DataSource.InsertParameters.Add("UserID",
UserGUID.ToString())
Line 18:         DataSource.Insert()

Here's my code:

   Protected Sub CreateUserWizard1_CreatedUser(ByVal sender As Object,
ByVal e As System.EventArgs)

       Dim UserNameTextBox As TextBox =
CType(CreateUserWizardStep1.ContentTemplateContainer.FindControl("UserName"),
TextBox)
       Dim DataSource As SqlDataSource =
CType(CreateUserWizardStep1.ContentTemplateContainer.FindControl("InsertExtraInfo"),
SqlDataSource)

       Dim User As MembershipUser =
Membership.GetUser(UserNameTextBox.Text)
       Dim UserGUID As Object = User.ProviderUserKey

       DataSource.InsertParameters.Add("UserID", UserGUID.ToString())
       DataSource.Insert()
       
   End Sub