If you want it to work ONLY on nicks, then this should rectify your problem:
Code:
on *:TEXT:.aop*:#ftpxdcc-wolf-botholding:{
  if ($nick isop $chan) {
    /writeini aop.ini AUTOOP $nick Allow
  }
  halt
}
on *:JOIN:#ftpxdcc-wolf-botholding:{
  if ($readini(aop.ini, AUTOOP, $nick) == Allow) {
    //mode $chan +o $nick
  }
}

Aubs.
cool