The requirements for AA are:
- Point Blank Shot feat
- Weapon Focus Longbow or Shortbow
- Any elven race (elf, avariel, drow, feiri etc)
- Base Attack Bonus = 6
- ability to cast 1 level arcane spells
There is a small glitch with spontaneous casters - you have to initialize the spell book: when you try to cast a spell for the first time (doesn't matter how many times you have rested before), you'll get "you have no casting of **** left" message, just rest after that and you should have your spells available (and should be able to choose arcane archer).