Its when you regularly consume three or more alcoholic beverages per day.
Alcohol and acetaminophen are both hepatoxic, meaning they both harm your liver and when taken in combination likely do more harm then when taken alone.
http://www.tylenoldanger.com/html/alcohol.html
Then you have the whole ulcer and stomach bleeding issue. Im sure this is unlikely to happen if you do it once but dont make a habit of it.