There's at least one wrong location shown in the map guide and another one location not shown in the picture... one near Anton Grimbite(?) and the other near a teak tree somewhere at G3. The text guide covers all possible locations as far as I remember, but not the map picture.
I have also had problems finding the dead dragon. I will usually find it after a day or two. It se ems that the dragon can be quite a ways from the sites listed in the wiki. Maybe if you expand your search radius you will find it.