The easiest solution would be to delete the ~/.kde file.
No need to delete all of your configuration files. As a brute force test, just exit X/KDE and rename the ~/.kde directory.
I'll take a wild first guess the problem is a corrupted saved session. Exit X/KDE and then delete your user sessions. They are stored in $HOME/.kde/share/config/session
. When you exit KDE, do not save the current session.
The problem lies with the kcheckpass . . .
There are also kcheckpass
files located in /var/run
and will have a file extension of the user ID (UID): /var/run/kcheckpass.UID
. You might want to delete those files too.