Really old thread, but I now found out what to do, and how to make Gibbon working on my system. (Arch Linux). Maybe I will make a PKGBUILD file for it later.
Gibbon is depending on gsettings-desktop-schemas. Your system probably have a deb/rpm/pacman for that.
gibbon comes with a .xml file. bg.gibbon.gschema.xml. In my build this was installed in /usr/local/share/glib-2.0/schemas/ (after 'make install')
Move this file to the directory containing the gsettings-desktop-schemas .xml files. On my system they are in /usr/share/glib-2.0/schemas/org.gnome.desktop.<...>.xml
So:
$ sudo mv /usr/local/share/glib-2.0/schemas/bg.gibbon.gschema.xml /usr/share/glib-2.0/schemas/
then you have to "compile" these schemas.
$ sudo glib-compile-schemas --targetdir=/usr/share/glib-2.0/schemas/ /usr/share/glib-2.0/schemas/
YMMV.
After that gibbon starts up with no problem.
Good luck and thanks to Guido for his effort with this client.
-Øystein