Hi buzztone,
Sorry but I think you misunderstood. There is no problem with the email notifications. It's the on-screen notification message that tells the visitor that the form was successfully submitted.
It is very odd that the error notifications work but the success notification doesn't.
The generated code includes the two <div> elements as per my second post. The class "wpcf7-mail-sent-ok" is applied correctly, but the div element is empty and has the style attribute "display:none".