If you, like me, already upgrade to Ubuntu Gutsy, and use nxclient for remote login (highly recommended, though proprietary code), you might run into the problem that the login no longer works, returning the message “Cannot find KDE environment.”. Ubuntu’s Lauchpad (generally an excellent service) was rather uncooperative and disregarded a bug report about the problem, I found the solution with grep -ri kde /usr/NX:

/usr/NX/etc/node.cfg:CommandStartKDE="/usr/bin/dbus-launch --exit-with-session startkde"

The solution was to:

sudo aptitude install dbus-x11

which contains the dbus-launch executable, formerly found in the dbus package itself. I assume it works for “Cannot find GNOME environment” too.