There are several Orc camps through out the whole map. I have just passed for my first time the whole battle situation at level 60 and it was very good, followed the path of the female Orc Tarish. so what you need to do for the preparations before the battle(60th week) is :
1st find the certain camp. Walk all the way up to the North following the road, find the crossroad and the river, pass the bridge and the monastery just 2 tiles away is the Orc camp NW of the monastery. (North in maps is always the top of the map)
2nd enter the camp and choose which chief you want to support. You will have to to re-visit the camp several times in order to complete the support and trigger the Orcs to join your cause. After the join you win the battle.
3rd Best to visit the camp early in the game and I don't know if it is essential but go also to the capital Rastedel between your visits to the Orc camp.
p.s. as A360 already said the camp looks the same with any other. It works so I don't see a possibility of bug