Package:
gajim 0.14.1-3

Error:
D-Bus python bindings are missing in this computer
D-Bus capabilities of Gajim cannot be used
/usr/lib/python2.7/site-packages/gajim/gtkgui_helpers.py:49: GtkWarning: Could not find the icon 'gajim-muc_separator'. The 'hicolor' theme
was not found either, perhaps you need to install it.
You can get a copy from:
http://icon-theme.freedesktop.org/releases
return gtk_icon_theme.load_icon(icon_name, size, 0)
18:57:43 (E) gajim.gtkgui_helpers Unable to load icon gajim-muc_separator: Icon 'gajim-muc_separator' not present in theme
18:57:43 (E) gajim.gtkgui_helpers Unable to load icon gajim-receipt_missing: Icon 'gajim-receipt_missing' not present in theme
18:57:43 (E) gajim.gtkgui_helpers Unable to load icon gajim: Icon 'gajim' not present in theme
Traceback (most recent call last):
File "gajim.py", line 414, in <module>
interface = Interface()
File "/usr/lib/python2.7/site-packages/gajim/gui_interface.py", line 3523, in __init__
gtk.window_set_default_icon(pix)
TypeError: window_set_default_icon() argument 1 must be gtk.gdk.Pixbuf, not None

Solution:
Apparently Gajim requires hicolor-icon-theme as a runtime dependency.

Additional info:
I discovered this error while doing a fresh install of Parabola GNU/Linux today. After installing xorg and lxde I installed gajim and tried to run it, which produced the error provided above. As I see hicolor-icon-theme is not a dependency of the ArchLinux gajim package so most probably this affects Arch too.