Thread: crashing when switch music type

Ok, in my game I have so you can select a mid or wav file to play as music. For some reason if I open a mid, another mid and a wav it crashes. I'm using the Windows API and fmod to play my music.

Is there anything wrong with my method of accomplishing things?
In my program I have an integer to track whether the current file is a mid or wav and then in my Windows procdure I use the approiate functions to the play the right type music.

Code:

#define MUSIC_MID 0
#define MUSIC_WAV 1
int music_type = 0;

   if(GetOpenFileName(&ofn))
   {   
      FSOUND_Sample_Free(wav_music);         
      FMUSIC_FreeSong(music);         
          
      if(strstr(szFileName,".wav"))
      {
         musicType = MUSIC_WAV;
         wav_music = FSOUND_Sample_Load(2,szFileName,FSOUND_LOOP_NORMAL, 0, 0);
         FSOUND_PlaySound(2,wav_music);               
      }
      else if(strstr(szFileName,".mid"))
      {           
         musicType = MUSIC_MID;
         music = FMUSIC_LoadSong(szFileName);
         FMUSIC_SetLooping(music,TRUE);
         FMUSIC_PlaySong(music);
      }
   }