Ah, i guess i completely overlooked the other coding mistake because i simply assumed the rest of the code was correct, there is no such identifier as $user, i think what you are looking for is $nick.

Code:
on 1:TEXT:%mp3sendtrig:#:{
  if %mp3sendyn == on {
    if %wanow != nothing {
      var %file = $nopath(%wafile)
      var %check = $readini(ini\songs.ini,%file,[color:red]$nick[/color])
      if (%check != true) {
        /writeini -n ini\songs.ini " $+ %file $+ " [color:red]$nick[/color] true
        /dcc send $nick %wafile
      }
    }
  }
}

"Allen is having a small problem and needs help adjusting his attitude" - Flutterby