Hacking Brawlbox BRSAR extracting?

[Khangaroo]

First off, I'm much, much more active in the 3DS homebrew scene so I am a noob.

I'm trying to export BGM from a .brsar file using BrawlBox, but it will always error out.

Spoiler

Object reference not set to an instance of an object.
at System.Audio.WAV.ToFile(IAudioStream source, String path, Int32 samplePosition, Int32 maxSampleCount)
at BrawlLib.SSBB.ResourceNodes.RSARSoundNode.Export(String outPath)
at BrawlBox.GenericWrapper.OnExport(String outPath, Int32 filterIndex)
at BrawlBox.GenericWrapper.Export()
at BrawlBox.GenericWrapper.ExportAction(Object sender, EventArgs e)
at System.Windows.Forms.ToolStripItem.RaiseEvent(Object key, EventArgs e)
at System.Windows.Forms.ToolStripMenuItem.OnClick(EventArgs e)
at System.Windows.Forms.ToolStripItem.HandleClick(EventArgs e)
at System.Windows.Forms.ToolStripItem.HandleMouseUp(MouseEventArgs e)
at System.Windows.Forms.ToolStripItem.FireEventInteractive(EventArgs e, ToolStripItemEventType met)
at System.Windows.Forms.ToolStripItem.FireEvent(EventArgs e, ToolStripItemEventType met)
at System.Windows.Forms.ToolStrip.OnMouseUp(MouseEventArgs mea)
at System.Windows.Forms.ToolStripDropDown.OnMouseUp(MouseEventArgs mea)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ScrollableControl.WndProc(Message& m)
at System.Windows.Forms.ToolStrip.WndProc(Message& m)
at System.Windows.Forms.ToolStripDropDown.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Am I missing something?