Season both sides of the walleye with salt and freshly ground black pepper. Coat both sides of the walleye fillet with flour. Heat the butter in a medium nonstick skillet over medium-high heat and cook the walleye on one side for 2 to 3 minutes, or until golden. Turn the fillets over and cook until fish is opaque and cooked through. Remove to a plate and keep warm. Add the garlic, sliced mushrooms and diced tomatoes to the fish pan and cook until mushrooms are golden and most of the liquid has evaporated. Add the bouillon, wine and lemon pepper and simmer until thickened and reduced. Salt and pepper to taste. Serve over linguini and top with the pan sauce. Makes 2 servings.