Is it recommended to put frozen fruit in a food processor?
According to KitchenAid's food processor users' manual:


  Never process any food that is so hard or firmly frozen that it cannot
  be pierced with the tip of a sharp knife. Hard food can cause damage
  to the blade or motor. If a piece of hard food, such as carrot,
  becomes wedged or stuck on the blade, stop the processor and remove
  the blade. Carefully remove food from the blade.


KitchenAid 12-cup Food Processor Manual

That being said, I've also used my food processor for frozen fruit, hard nuts, etc.  My blades have never worn out in 18 years of use (though the bowl has been replaced once due to cracking).