In your home directory, you have a file called .xinitrc. Since the name begins with a dot you cannot see it in the Finder, but you can edit it by typing
pico ~/.xinitrc
in the terminal.
You don't mention how you installed X11, but it seems to me that you have an .xinitrc that thinks that you have kde installed - and installed via Fink, at that - while you don't really have it installed.
Either modify your xinitrc, if you know how, or replace it with the default from /private/etc/X11/xinit/xinitrc