I'm running Fedora F16 (with XFCE rather than Gnome 3) and ever since I installed it I've been getting errors like this one whenever I run GUI software from the terminal:

```
(file-roller:4828): Gtk-CRITICAL **: gtk_style_provider_get_style_property: assertion `g_type_is_a (gtk_widget_path_get_object_type (path), pspec->owner_type)' failed
(file-roller:4828): Gtk-CRITICAL **: gtk_style_provider_get_style_property: assertion `g_type_is_a (gtk_widget_path_get_object_type (path), pspec->owner_type)' failed
(file-roller:4828): Gtk-CRITICAL **: gtk_style_provider_get_style_property: assertion `g_type_is_a (gtk_widget_path_get_object_type (path), pspec->owner_type)' failed
(file-roller:4828): Gtk-CRITICAL **: gtk_style_provider_get_style_property: assertion `g_type_is_a (gtk_widget_path_get_object_type (path), pspec->owner_type)' failed

```

This particular error was from opening a zip file using `gnome-open`, while opening `gedit` gives no error on launch, but the following error on every save operation:

```
** (gedit:4900): CRITICAL **: gedit_spell_checker_language_to_key: assertion `lang != NULL' failed

```

I'm not 100% sure they're related, but I've been getting a lot of these and it seems basically any GUI program is likely to have one or more "CRITICAL" error before starting up so something fundamental seems to be broken somewhere I just don't even know where to start. Does anyone have any ideas of how to track this down?