The Dire Maul Arena, where Skarr spawns, is located OUTSIDE of the Dire Maul instance, in the courtyard.
Do not go inside of an instance.
Take the road from Feathermoon or Mojace, and turn up the main path towards the Dire Maul zone. You'll go on big stone pathway past a bunch of orcs. At one point you will see that the path splits and forms a rectangle, you are entering the rectangle on a patch from the south. Head all the way around the rectangle and leave the rectangle heading north. The arena is right there, can't msis it.
43,67 in Feralas
Do not go inside of an instance.
Take the road from Feathermoon or Mojace, and turn up the main path towards the Dire Maul zone. You'll go on big stone pathway past a bunch of orcs. At one point you will see that the path splits and forms a rectangle, you are entering the rectangle on a patch from the south. Head all the way around the rectangle and leave the rectangle heading north. The arena is right there, can't msis it.
43,67 in Feralas