Just taking a very quick glance, I'd say the problem is that when you call ButtonClick_Yes, you don't pass the Item



USERFORM1
 
Public Sub CommandButton1_Click()
    ButtonClick_Yes MISSING AN ITEM <<<<<<<<<<<<<<<<<<
End Sub


MODULE1
 
Public Sub ButtonClick_Yes(ByVal Item As Object)
Dim objFollowUpMail As Outlook.MailItem


Set objFollowUpMail = Application.CreateItemFromTemplate("Example.oft")
With objFollowUpMail
.To = Item.Recipients.Item(1).Address
.Subject = "Follow Up: " & Chr(34) & Item.Subject & Chr(34)
.Attachments.Add Item
.HTMLBody = "Example"
.Display
End With
End Sub
BTW, I added CODE tags to my reply. You can use the [#] icon to insert them and paste your macro between