Determine Safety and Effectiveness of Tadalafil in Asian Men When Taken as Needed for Getting and Keeping an Erection

Inclusion Criteria: * History of erection problems * Anticipate a monogamous female sexual relationship * Abstain from other erection treatments at least 4 weeks before first dose and throughout the study * Must be able to make required sexual intercourse attempts Exclusion Criteria: * Other primary sexual disorders * History of radical prostatectomy or other pelvic surgery that affected being able to have an erection * History of penile implant or clinically significant penile deformity * Nitrate use * Certain heart problems