Yes, that command works perfect. However, trying to run vanilla kdesu dolphin still doesn't work afterwards.
I can live with kdesu dbus-launch dolphin until the next release.
edit: UPDATE, Konqueror is now working in super user mode without any problems. Perhaps deleting the /root/.kde4.2 folder fixed it?
I also find it weird that the bug doesn't happen to everyone.
Thanks everyone for helping me.