Comment 1 for bug 176135

Confirming the issue. I've just installed latest KDE4 from PPA.
File /usr/lib/kde4/bin/startkde (belongs to kdebase-workspace-bin), line 82 reads:
. $kdehome/share/config/startupconfig

This file is initially missing. The problem is, that this script is run by /bin/sh, not /bin/bash and sh terminates a script, when it tries to source a non-existent file. Either an interpreter should be changed to bash (on the 1st line: #!/bin/bash), or the line should be changed to:
[ -e $kdehome/share/config/startupconfig] && . $kdehome/share/config/startupconfig

Importance of this bug should be increased (but it looks like I don't have an appropriate permissions), because this will totally prevent KDE 4 session from being started. However, it's quite easy to fix (see above).