Well, I told you in another post, that 3.4 GB is not enough! You're running low with space.
KDE-themes usually work not with Mandriva when installed from tarballs. You should not be bothered with autologin. Try to reinstall Mandriva, but without rush! Calm down, please. Obtain enough places for your new installation. Everything will O.K. You may have only 1 NTFS partition with Mandriva 2008. Consider this.