 This study investigates the safety and efficacy of a new dosage form of Vardenafil, an orodispersible tablet ODT, and compares it to the safety and efficacy of a placebo inactive tablet in the treatment of erectile dysfunction. After a 4-week unmedicated phase, patients will receive Vardenafil ODT or matching placebo for 12 weeks. Safety will be determined by laboratory and other evaluations. Efficacy will be determined by the results of different questionnaires and the patient diary that will be used. 