Bring broth to a boil and add artichokes, corn, salt and pepper. Simmer for 15 minutes. Heat oil in another pan and saute onions and garlic for 2 minutes. Add peppers, scallions and celery. Saute for 5 minutes. Add cooked vegetables to the stock pot. Return stew to a boil, add the crawfish. Stir well, lower heat and cook for 5 minutes. Remove from heat and add dill, thyme, oregano, and allspice. Add the file powder, stir well. Serve topped with parsley, scallions and a dash of cayenne.