Comment 7 for bug 56206

Thanks to http://www.kde-forum.org/thread.php?threadid=15137

The problem is that ~/.kde/share/config/kpersonalizerrc does not have a [General] section, which should look like this by default:

[General]
FirstLogin=true

Because it is not there kpersonalizer cannot set it to false. Add this to kpersonalizerrc to fix the problem for one user:

[General]
FirstLogin=false

The real bug is how the user's kpersonalizerrc is generated:
The default kpersonalizerrc is generated from /usr/share/kubuntu-default-settings/kde-profile/default/share/config/kpersonalizerrc. That file looks like this:

[General]
FirstLogin=false

(i.e. Kubuntu maintainers don't want kpersonalizer starting for every user)
For some reason this doesn't work and the generated kpersonalizerrc doesn't contain the [General] section, causing this problem. If you change false to true in the global kpersonalizerrc, new users' generated kpersonalizerrc will contain the [General] section.