Official Title: A Multi-center, Open-Labeled Exploratory Study to Investigate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics Following Oral Administration of PSI-7977 400 mg and Ribavirin for 12 Weeks With and Without Pegylated Interferon in Treatment-Naïve Patients With Chronic HCV Infection Genotype 2 or Genotype 3