It's dublicated from KDE Bug Tracking, bug id 167719. KDE 4.1 from kde-redhat. 
This bug is apsent in KDE 3.5.*.

I have home mounted with autofs which gets information from LDAP. When I trying 
to start KDE I get only splash window and bakground image. Splash in about one 
minute will disappear and only backround image is what I have. I cleaned out 
all my preferences, it did not helped. At the same time root login is fine. 
Looking at ~/.xsession-errors I see many errors whith dbus like: 

<unknown program name>(18011)/: Communication problem with  "krunner" , 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." " 

Or: 

kdeinit4: preparing to launch /usr/bin/plasma 
plasma(18093): Communication problem with  "plasma" , 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." " 

And all stopped on: 

QDBusConnection received a message of type 2 that it shouldn't have 
*** PULSEAUDIO: Unable to connect: Connection refused 
*** Is your sound server running? 
*** See: http://www.pulseaudio.org/wiki/Troubleshooting 

Also, there are following "E" messages apear at the beginning: 
E: polkit.c: Cannot connect to system bus: 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. 
E: main.c: daemon startup failed. 

Others DE or WM starts fine.