I also had same problem.
And i fix it by adding additional try-exept block to "avant-window-navigator/awn-settings/awnClass.py" where 'gtk-missing-image' is loading.
I also had same problem.
And i fix it by adding additional try-exept block to "avant- window- navigator/ awn-settings/ awnClass. py" where 'gtk-missing-image' is loading.