Is this a paid app, if so pay for it on the market/amazon and you should have no problem, piracy is bad...if it is a free app download it from the market/amazon and you should have no problem, piracy is bad.
If you are trying to pirate an app perhaps some general knowledge about how people get around extensions that are not allowed on file sharing sites would be something to learn but I would still suggest just getting the app from the market or amazon