Well, the film indicates that it could have only been tracked if they replied. Like I say, you can make up a reason like that if you want, but you shouldn't HAVE to, it should have been explained in film.
Also, seeing as that message wasn't actually sent at anything in particular (it can't have been, because of course they did not know where the Queen's Ship WAS), it probably was recieved by lots and lots of people, so a listening trace would have been not much good.
BTW, the second time the message was played was a. a recording, b. when the ship was in flight and c. was AFTER Maul had already found them!