Are you using the 3gx gyro? If so there is a chance you did not properly setup the gyro.
Here is a link to a great video on the gyro setup along with the mechanical setup and controller settings. I suggest you follow along step by step and learn the why and how. If you just blindly copy someones config you will not get where you want to be, Don't worry that its not the same size helicopter, it will help you out. There are a few videos in this playlist.