I just try your plugin ans I see 2 troubles for the moment :
1- When someone post an Ad, he never receive New ad subject template and New ad template Custom mail (enable in your plugin).
But when an Admin Accept an Ad, New ad template admin is Sent normally.
2 - New ad template admin :
I receive the custom mail but something appear strange in the object "=?UTF-8=" ...... (see printscreen please).