Hi there,
Use this code.
Code:
alias err {
  if ($1 == 1) {
    if $exists($qt(sound.mp3)) {
      splay -q $qt(sound.mp3)
    }
    else { echo -a Error }
  }
  elseif ($1 == 2) {
    if $exists($qt(sound.mp3)) {
      splay -q $qt(sound.mp3)
    }
    else { echo -a Error }
  }
}


PS: if $2 == 1 will not be supported like this, you need to use if ($1) && ($2) then if ($2 == <value>) etc.. but this code I posted for you shall work.