"NameError: name 'vfs_exists' is not defined" bug or issue on my system

been trying to convert a video file with opus audio to mp3. Updated gstreamer with a ppa, and built Soundconverter for source to see if it would work. Woundering if this is a bug in the alpha1 or an issue on my end. Here is the output:

SoundConverter 3.0.0-alpha1
  using GTK version: 3.0
  using Gstreamer version: 1.6.3.0
  using 12 thread(s)
  using gio
  "lame" gstreamer element not found, disabling MP3 output.
  "faac" gstreamer element not found, disabling AAC output.
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/usr/local/lib/soundconverter/python/soundconverter/ui.py:1482: Warning: g_value_type_transformable: assertion 'G_TYPE_IS_VALUE (src_type)' failed
  builder.add_from_file(gladefile)

(python3:11425): Gtk-WARNING **: /tmp/buildd/gtk+3.0-3.10.8~8+qiana/./gtk/gtkliststore.c:848: Unable to convert from (null) to gchararray

/usr/local/lib/soundconverter/python/soundconverter/ui.py:1482: Warning: g_value_unset: assertion 'G_IS_VALUE (value)' failed
  builder.add_from_file(gladefile)
Queue start: 1 tasks, 12 thread(s).
Pipeline.play
Queue done in 0.014s (1 tasks)
Traceback (most recent call last):
  File "/usr/local/lib/soundconverter/python/soundconverter/ui.py", line 1354, in on_convert_button_clicked
    self.do_convert()
  File "/usr/local/lib/soundconverter/python/soundconverter/ui.py", line 1336, in do_convert
    self.converter.add(sound_file)
  File "/usr/local/lib/soundconverter/python/soundconverter/gstreamer.py", line 663, in add
    output_filename = self.window.prefs.generate_temp_filename(sound_file) + '~SC~'
  File "/usr/local/lib/soundconverter/python/soundconverter/ui.py", line 758, in generate_temp_filename
    if not vfs_exists(filename):
NameError: name 'vfs_exists' is not defined