Буквы в окнах gtk отображаются квадратами

На моем компьютере установлен Linux. Занимаюсь программированием на Python именно в этой операционной системе. Естественно, приходится тестировать написанные приложения и в среде Windows. Было решено установить Wine и Python for Windows. Так вот, собственно, проблема: при использовании библиотеки gtk (Wine/Python) вылазят вот такие предупреждения... Сам шрифт в окнах интерфейса в квадратах, будь то кириллица либо же латиница.

Warning (from warnings module):
  File "Z:\home\zavulon\Programming\Opt\Package_for_Windows\gtkPopupNotify-master\gtkPopupNotify.py", line 248
    self.show_all()
PangoWarning: couldn't load font "Sans Bold Not-Rotated 14", falling back to "Sans Bold Not-Rotated 14", expect ugly output.

Warning (from warnings module):
  File "Z:\home\zavulon\Programming\Opt\Package_for_Windows\gtkPopupNotify-master\gtkPopupNotify.py", line 248
    self.show_all()
PangoWarning: All font fallbacks failed!!!!

Warning (from warnings module):
  File "Z:\home\zavulon\Programming\Opt\Package_for_Windows\gtkPopupNotify-master\gtkPopupNotify.py", line 248
    self.show_all()
PangoWarning: failed to choose a font, expect ugly output. engine-type='PangoRenderWin32', script='latin'

Warning (from warnings module):
  File "Z:\home\zavulon\Programming\Opt\Package_for_Windows\gtkPopupNotify-master\gtkPopupNotify.py", line 248
    self.show_all()
PangoWarning: couldn't load font "Sans Not-Rotated 12", falling back to "Sans Not-Rotated 12", expect ugly output.

Warning (from warnings module):
  File "Z:\home\zavulon\Programming\Opt\Package_for_Windows\gtkPopupNotify-master\gtkPopupNotify.py", line 373
gtk.main()
PangoWarning: couldn't load font "Sans Bold Not-Rotated 10", falling back to "Sans Bold Not-Rotated 10", expect ugly output.

Warning (from warnings module):
  File "Z:\home\zavulon\Programming\Opt\Package_for_Windows\gtkPopupNotify-master\gtkPopupNotify.py", line 373
    gtk.main()
PangoWarning: All font fallbacks failed!!!!

Warning (from warnings module):
  File "Z:\home\zavulon\Programming\Opt\Package_for_Windows\gtkPopupNotify-master\gtkPopupNotify.py", line 373
    gtk.main()
PangoWarning: failed to choose a font, expect ugly output. engine-type='PangoRenderWin32', script='common'