Prot# HCT 3012-X-301: A Phs 3 Stdy of the Analgesic Efficacy & Sfty of HCT 3012: A Parallel, Randomized, Double-Blind, 13-Wk, Placebo-& Naproxen-Controlled, Multicenter Study of HCT 3012 (375 mg bid & 750 mg bid) in Ptnts w/Osteoarthritis of the Knee