1. gdk-pixbuf-query-loaders --update-cache does NOT work with SliTaz 3. You have to use gdk-pixbuf-query-loaders > /etc/gtk-2.0/gdk-pixbuf.loaders as root instead. Even after doing so, it will try falling back on the ini file... which it REFUSES to create (obviously a bug) and thus fails badly.
2. It's clear it's not working for you michaelbischof, ESPECIALLY because you had to install Java, which has absolutely NOTHING to do with python (JPython maybe, but that's only a Python interpreter written in Java) at all.