Well for starters, you don't need two routines, which they're doing the same thing anyway, per ban and unban event. This will do the trick just dandy:

on *:BAN:#:banfinder
on *:UNBAN:#:banfinder
alias -l banfinder {
  var %x = 1
  var %nicks = $null
  while ($nick($active,%x)) {
    if ($banmask iswm $ial($banmask,%x)) {
      set %nicks $addtok(%nicks,$ialchan($banmask,$chan,%x).nick,32)
      inc %x
    }
    else {
      inc %x
    }
  }
  if (%nicks == $null) { halt }
  var %nicks = $replace(%nicks,$chr(32),$chr(44) $+ $chr(32))
  echo -t $chan $iif($event = ban,$+($chr(3),7,Ban),$+($chr(3),7,Unban)) $&
    of14 $banmask 07by14 $nick $+ ( $+ $remove($address($nick,1),*!*) $+ ) 07affects:14 %nicks $+ 07.
}