Just a short note. I tried to install the sesame backend for soprano on opensuse 11.1 factory (KDE 4.3.0). Since I installed the java openjdk-devel packed (thanks for the hint) and of cause soprano-backend-sesame Nepomuk runs perfectly well.
Second note: I'm really happy that openSUSE is a community based distro and is (again) selecting KDE as the default while installation. Gnome is still at the top of the list but it's a great sign. If you are not an openSUSE user you might give it a try.