nautilus gone!

[Gerhard Magnus]

I've just installed FC9 with the gnome desktop. I don't think I've done
much of anything yet besides putting some stuff in the panel, turning on
the network service (and disabling network manager), setting up the yum
repositories and yum priorities, removing bluez-libs and pcmiautils (I'm
not using laptops) and installing yumex. The next time I boot the
desktop icons are gone, clicking the right mouse button on the desktop
has no effect, and nautilus seems to be gone. (I can't start it from the
command line either.) 

What's going on? How can I get my desktop and file manager back?

Thanks for the help!
Jerry