[Solved] Not all Order Emails or Status are Sent

[Rhapsody]

I've upgraded to 1.3.6 and have this problem on two different servers that I run PrestaShop.

1. Orders that have PayPal as payments successfully generate the customer notification email. The shop gets a payment accepted status from the PayPalAPI, but no PrestaShop email to the store owner is generated. PayPal sends a confirmation email of the order.
2. Orders paid by check generate the "Awaiting Check Payment" status in the BO. The shop owner gets the order email indicating an order by check. The customer gets the invoice email. There is never an email sent for awaiting check payment status message.

In the BO I verified that the various status messages have the proper templates assigned (e.g. payment for payment accepted and cheque for awaiting check payment). The check boxes to "Send e-mail to customer when order is changed to this status" are checked, but it appears none of these emails are transmitted. If I manually change the status of the order, there are no emails sent either. The shop does send some messages, so the mail server is properly configured.

Can anyone tell me what files have the code that is supposed to trigger the email so I can troubleshoot. Are there any troubleshooting ideas out there?

---------------Edit below on what I found as the problem--------------
I am now running 1.4.2.0 after various incremental updates and have solved the problem on on of my two shops. We have a Gmail account being used for the shop email address. It seems that gmail updated the spam filters and all the mails were going there. I fixed the gmail filer and now have the mail alerts working properly.

[Tom_Rufener]

I also had some problems regarding customer emails and order statuses in 1.3.6 - the first release of 1.3.6 was buggy. Re-downloading the whole Prestashop 1.3.6-package and re-uploading the "classes" (ONLY the "classes", nothing else) folder via FTP solved it for me.

[Ashton MotorClothing]

Thanks to you Thomas_Rufener, i had the same problem and now it's ok, thanks again.

[weit]

Also, thank you very much for your advice, I had the same problem.

This is an incorrect definition of "OrderHistory.php.
It will help update the new version 1.3.7. Attach..

OrderHistory.php

[rcsa]

I also had some problems regarding customer emails and order statuses in 1.3.6 - the first release of 1.3.6 was buggy. Re-downloading the whole Prestashop 1.3.6-package and re-uploading the "classes" (ONLY the "classes", nothing else) folder via FTP solved it for me.

Can you explain this please? DO you mean I have to download the whole Prestashop package? How do i do that? And what are classes?

Thank you!

[Rhapsody]

I am now running 1.4.2.0 after various incremental updates and have solved the problem on on of my two shops. We have a Gmail account being used for the shop email address. It seems that gmail updated the spam filters and all the mails were going there. I fixed the gmail filer and now have the mail alerts working properly.