The default /etc/nxserver/node.conf in net-misc/nxserver-freenx-0.5.0-r1 does not properly identify kde. I had to change it to the following for it find kde: COMMAND_START_KDE="/usr/bin/ssh-agent /usr/bin/dbus-launch --exit-with-session /usr/kde/3.5/bin/startkde" I would prefer using something like $KDEHOME/bin/startkde as I noticed $KDEHOME earlier in the script, but it did not work.
This will be fixed in nxserver-freenx-0.5.0-r2, which I am currently testing locally. Best regards, Stu