Fixed some errors

Assets/Scripts/GameManager.cs

@@ -230,6 +230,7 @@ namespace RhythmHeavenMania
         public void Pause()
         {
             Conductor.instance.Pause();
+            KillAllSounds();
         }
 
         public void Stop(float beat)
@@ -244,6 +245,8 @@ namespace RhythmHeavenMania
         {
             for (int i = 0; i < SoundObjects.Count; i++)
                 Destroy(SoundObjects[i].gameObject);
+            
+            SoundObjects.Clear();
         }
 
         #endregion

Assets/Scripts/Util/Jukebox.cs

@@ -109,6 +109,10 @@ namespace RhythmHeavenMania.Util
 
         public static void KillLoop(AudioSource source, float fadeTime)
         {
+            // Safeguard against previously-destroyed sounds.
+            if (source == null)
+                return;
+
             source.GetComponent<Sound>().KillLoop(fadeTime);
         }
     }