Hey there,
I am really sorry for the delay of this reply as it is a weekend for us here.
We did changed the email post approved/rejected file name in next release version, I already attached those fix file in my reply, can you try download those files and replace into following file location?
post.php
- JoomlaFolder/administrator/components/com_easydiscuss/includes/post/post.php
email.post.approve.html.php
email.post.approve.php
email.post.rejected.html.php
email.post.rejected.php
- JoomFolder/components/com_easydiscuss/themes/wireframe/emails/...
By the way, these all fix will included in next release version as well.