Icon 'gtk-close' not present in theme

I recently started to use screenlets again, especially FreeMeteo for weather forecast. But on ubuntu 12.04 every time I login I get a crash message:

FreemeteoWeatherScreenlet.py crashed with GError in load_buttons(): Icon 'gtk-close' not present in theme

If you have a similar crash message, you can simply install the gnome-icon-theme-full package which contains the gtk-close.png file.

Source: https://bugs.launchpad.net/ubuntu/+source/indiv-screenlets/+bug/807129