So I'm having trouble with permissions with applications, this seems to be following me around as I had the same problem while running openSUSE 13.2 until I upgraded to LEAP 42.2 3 days ago and I have never quite gotten a permanent solution.
I managed to boot up my laptop but got the errors below;

Configuration file "/home/username/.kde4/share/config/knotifyrc" not writable.Please contact your system administrator.

I tried to start one of the applications - VirtualBox but got this instead

Configuration file "/home/username/.config/VirtualBoxrc" not writable.

Please contact your system administrator.

Please help. Thanks.