An LLC or other form of corporation does not, of itself, protect you from liability for your own acts. By way of example, if your corporation owns a car and you negligently crash it, the victims of the crash can sue both you and your corporation.
Also, it's possible to ask a court to set aside the corporate shield when a business entity is a mere alter ego of the person who incorporated the entity, and was used to commit tortious conduct.
Setting up a LLC will not allow you to commit copyright violations, trademark and patent infringement with impunity.
Beyond that, laws vary by state.

