When I issued startx from a tty session I received the following
messages in .xsession-errors after kde4 failed to start:

klauncher(7391)/kio (KSycoca) KSycocaPrivate::openDatabase: Trying to
open ksycoca from "/var/tmp/kdecache-steve/ksycoca4"
kdeinit4: Got EXEC_NEW 'kconf_update' from launcher.
kdeinit4: preparing to launch /usr/lib/kde4/libexec/kconf_update
klauncher(7391)/kio (KLauncher) KLauncher::processRequestReturn:
"kconf_update" (pid 7399) up and running.
kded(7392): Communication problem with "kded" , it probably crashed.
Error message was: "org.freedesktop.DBus.Error.NoReply" : " "Did not
receive a reply. Possible causes include: the remote application did not
send a reply, the message bus security policy blocked the reply, the
reply timeout expired, or the network connection was broken." "

kdeinit4: PID 7392 terminated.
kdeinit4: preparing to launch /usr/bin/kcminit_startup
kdeinit4: Launched 'kcminit_startup', pid = 7406 result = 0
kcminit(7407)/kio (KSycoca) KSycocaPrivate::openDatabase: Trying to open
ksycoca from "/var/tmp/kdecache-steve/ksycoca4"
kdeinit4: Got SETENV 'KDE_MULTIHEAD=false' from klauncher.
kdeinit4: PID 7406 terminated.
kdeinit4: Got KWRAPPER 'ksmserver' from socket.
kdeinit4: preparing to launch /usr/bin/ksmserver
<unknown program name>(7390)/ KStartupInfo::createNewStartupId:
creating:
"development.geelong.highton.org.au;1212289780;473006;7390_TIME0" :
"unnamed app"
ksmserver: symbol lookup error: /usr/lib/nvidia-current/libGLcore.so.1:
undefined symbol: _nv000042gl
kdeinit4: PID 7410 terminated.
startkde: Shutting down...
kdeinit4: terminate KDE.
klauncher: Exiting on signal 1
kded(7393): "KLauncher could not be reached via D-Bus. Error when
calling kdeinit_exec_wait:
empty
"

regards,
Steve