ssh X11 forwarding does not work for KDE applications

[lsmod]

I can establish a shell ssh-connection from one PC running Lucid to another PC running Lucid.
I open the shell with ssh -X user@pc.
On the remote PC i can open a X11 application like xclock and this works.
But when i try to open a KDE-application then it crashes with the following message:

~$ kate
kate(2966): Session bus not found

KCrash: Application 'kate' crashing...
sock_file=/home/user/.kde/socket-PC12/kdeinit4_localhost_10
Warning: connect() failed: : No such file or directory
KCrash cannot reach kdeinit, launching directly.
drkonqi(2968): Session bus not found

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: openssh-server 1:5.3p1-3ubuntu4
ProcVersionSignature: Ubuntu 2.6.32-25.45-generic 2.6.32.21+drm33.7
Uname: Linux 2.6.32-25-generic x86_64
NonfreeKernelModules: nvidia
Architecture: amd64
Date: Thu Dec 2 11:46:46 2010
InstallationMedia: Kubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100427)
ProcEnviron:
 LANGUAGE=
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: openssh

[lsmod (forum+ubuntu)]

It also does not work trying the option "-4" from this bug report:
https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/657302

tail -3 /etc/init/ssh.conf

add -4 to the last line
exec /usr/sbin/sshd -4

[Scott Moser (smoser)]

I'm marking this as kdebase, it almost certainly is not a bug in openssh that is causing the failure.

[lsmod (forum+sf)]

I have the same problem in Debian now.
Please refer to http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=609422

[Harald Sitter (apachelogger)]

Hi there!

Thanks for reporting this bug! Your bug seems to be a problem with the KDE program itself, and not with our KDE packages. While we appreciate your issue, it would be better if it was tracked at https://bugs.kde.org, so that the KDE developers can deal with this speedily and have direct communication with you as the reporter for more effective debugging.

Thanks!