Try the following: logoff from KDE, then on a console session (say Ctl-Alt-F1), rename your .kde directory: "mv .kde .kde.bkp". Then logon graphically (Ctl-Alt-F7, KDM). Hopefully KDE will re-create a working default profile for you.

If this fails, I once had a similar problem which was fixed by the foillowing tip: http://www.mepis.org/node/view/1806#comment-6638

Hope this helps,

--bald