Minim Library NullPointerException upon loading file

Processing Libraries
1

Hi again, I seem to be having a problem with the minim library in Processing 3.0b5. I’ve properly loaded in my audio files, but when I start the game, it gives me this error in the syntax each time:

==== JavaSound Minim Error ====
==== Unable to return a SourceDataLine: unsupported format - PCM_SIGNED 44100.0 Hz, 16 bit, stereo, 4 bytes/frame, little-endian

=== Minim Error ===
=== Couldn't load the file beginning.mp3

==== JavaSound Minim Error ====
==== Unable to return a SourceDataLine: unsupported format - PCM_SIGNED 44100.0 Hz, 16 bit, stereo, 4 bytes/frame, little-endian

=== Minim Error ===
=== Couldn't load the file floor1.mp3

==== JavaSound Minim Error ====
==== Unable to return a SourceDataLine: unsupported format - PCM_SIGNED 44100.0 Hz, 16 bit, mono, 2 bytes/frame, little-endian

=== Minim Error ===
=== Couldn't load the file text.wav

Now, don’t say it’s the wrong directory yet! I have all of the files in the “data” folder inside the sketch, and yesterday it was working and loading the files properly (although I didn’t change anything overnight). The game i’m making is large, but i’ll share specifically what I did to load the minim/audio files.

import ddf.minim.spi.*;
import ddf.minim.signals.*;
import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.ugens.*;
import ddf.minim.effects.*;
Minim beginningm, f1m, textm;
AudioPlayer beginningp, f1p, textp;
void setup() { 
  beginningm = new Minim(this);
  beginningp = beginningm.loadFile("beginning.mp3");
  f1m = new Minim(this);
  f1p = f1m.loadFile("floor1.mp3");
  textm = new Minim(this);
  textp = textm.loadFile("text.wav");
  beginningp.loop();
}

There are obviously more instances of the audio files that I didn’t mention that come after this (mainly just pausing/playing different audio), but it gives me the error at the line that says

  beginningp.loop();

with a “NullPointerException” in the red bar. Any suggestions on what’s going wrong? (I did double check that I had the minim library in the “libraries” folder, and all of the audio files are named properly in the “data” folder inside the sketch folder.)