Saute green pepper in butter in large skillet. Dissolve flour in milk and add to the pepper. Stir over low heat until a thick paste is formed; set aside. Place crabmeat in a bowl and add seafood seasoning, mustard, 1 tbs mayonnaise, green pepper sauce and blend. Place mixture into small casserole dish. In another bowl, beat the egg and 3 tbs mayonnaise and spoon this over crabmeat mixture. Sprinkle with paprika. Bake at 350 degrees for 20 minutes.