Melt butter in heavy large skillet over medium heat. Add bell pepper; cover and cook 2 minutes. Add garlic and crushed red pepper; cover and cook 2 minutes. Increase heat to high, add wine and boil 2 minutes. Set aside. Cook pasta in large pot of boiling salted water until just tender but still firm to bite, stirring occasionally. Drain pasta, reserving 1/2 cup cooking water. Return pasta to pot. Add clam juice, 1/2 cup cooking water and bell pepper mixture. Cook over high heat until pasta absorbs half of liquid, about 2 minutes. Add crab and toss until heated through, about 1 minute. Mix in parsley. Season to taste with pepper. Divide pasta among bowls. Sprinkle with pine nuts. Serve, passing cheese separately.