In a small saucepan, melt 2 tablespoons butter or margarine. Stir in flour to make a paste. Set roux aside.
Saute mushrooms, Cajun spice, and garlic in 1/4 cup butter or margarine over medium-high heat for 2 minutes. Add oysters, corn, string beans, and pimento. Saute for 1 1/2 minutes. Add stock and linguine, and bring to a slight simmer.
Fold in roux until sauce thickens, then reduce heat. Fold in parsley and scallions. Fold in lump crabmeat, and heat through. Serve immediately.
