You should use /var instead of /set for things like this smile
Code:
  var %i = 1
  echo 2 -a 14,15==> OPS: 
  while ($nick(#,%i)) {
    var %nick = $ifmatch,%address = $address(%nick,1)
    if ($level(%address) == %OL) {
      .......
      .......
    }
    elseif ($level(%address) == %VL) {
      .......
      .......
    }
    inc %i
  }
  ...