Actually, the whole iTunes alias is a cluster f--k waiting to happen. He's not nagging. If you would've taken the time to look you closed the alias off before it even finishes checking everything. Like he said, all of the if statements after the first one are just not going to work at all. Why? You didn't even close off the if statements.. Honestly, they should be else statements in my opinion and just remove the !%var stuff all together... Oh and I see that there's a "/track" which would imply there's a "track" alias which isn't included in the coding at all. Also, why use a / to make it do an alias? $track works perfectly.

Also, if you look at your alias on line 26 there's a 3 on the outside of the bracket

}3

The alias doesn't even recognize that bracket. Deleting the 3 returns a bracket mismatch error at that point (I done this personally). I see no improvement. Are you sure you made this? Because you don't seem to be defending the fact it's messed up or even taken the action of fixing and cleaning it up.. but here... I'll do it for you..

alias itunes {
  ;Opens iTunes
  if ($1 == open) {
    .comopen itunes itunes.application
    .echo -a $comerr
  }

  ;Activates the play button within iTunes
  if ($1 == play) { 
    .set %play $com(itunes,PlayPause,3)
    /track
  }
  else { .echo -a iTunes may not be open. | halt }

  ;Plays the next track
  if ($1 == Next) { .set %next $com(itunes,NextTrack,3)
    /track
  }
  else { .echo -a iTunes may not be open. | halt  }

  ;Plays the previous track
  if ($1 == Previous) {
    .set %Previous $com(itunes,PreviousTrack,3)
    /track
  }
  else { .echo -a iTunes may not be open. | halt  }

  ;Stops the current track
  if ($1 == Stop) { 
    .set %stop $com(itunes,Stop,3)
  }
  else { .echo -a iTunes may not be open. | halt  }
}

I added comments, force of habit. Also, you're more than welcome to remove the spacing.. it works fine as is. Want a shorter version here you go:

alias itunes {
  ;--Opens iTunes--;
  if ($1 == open) { .comopen itunes itunes.application | .echo -a $comerr }

  ;--Activates the play button within iTunes--;
  if ($1 == play) { .set %play $com(itunes,PlayPause,3) | $track }
  else { .echo -a iTunes may not be open. | halt }

  ;--Plays the next track--;
  if ($1 == Next) { .set %next $com(itunes,NextTrack,3) | $track }
  else { .echo -a iTunes may not be open. | halt  }

  ;--Plays the previous track--;
  if ($1 == Previous) { .set %Previous $com(itunes,PreviousTrack,3) | $track }
  else { .echo -a iTunes may not be open. | halt  }

  ;--Stops the current track--;
  if ($1 == Stop) { .set %stop $com(itunes,Stop,3) }
  else { .echo -a iTunes may not be open. | halt  }
}

-.-