the error message is occurring because the sever has enabled safe mode. universal email cannot work with safe mode enabled, safe mode will need to be turned off.
if the files are looked, that probably means they are read only, right click them in dream weavers file panel and select the Turn Of Read Only option to unlock them.
could the national email be triggers on another page like the confirm page?
or double check for 2 instances of the UE code on the checkout_success_international.php page