I noticed the error (check log at the end) after running apt-get upgrade today, which is similar to yours.
Basically it upgraded some packages from thumb repository.
I don't have any issues with installation and when i run the commands given by micha they end without any errors.
But wondering if I should be creating /usr/lib/gtk-2.0/2.14.0/immodules directory ?

Below is the log:
Setting up libgtk2.0-bin (2:2.14.7-1maemo34+0cssu2+thumb0) ...
You don't have immodules directory for version 2.4.0.
Use default version instead.
Updating the IM modules list for GTK+-2.14.0...find: /usr/lib/gtk-2.0/2.14.0/immodules: No such file or directory
done.
You don't have gdk-pixbuf loaders directory for version 2.14.0.
Use default version instead.
Updating the gdk-pixbuf loaders list for GTK+-2.14.0...done.