can't start xfdesktop

ashunter

i have installed xfce4 and xfce4-goodies,follow this wiki http://wiki.archlinux.org/index.php/Xfce,
I choose xfce session in login screen,only black screen with two panels,no wallpaper,no icons...
the xfdesktop doesn't start automatic,then i want to start it myself,but i got these messages:
** Message: Querying Xkb extension
** Message: Xkb extension found
** Message: This build doesn't include support for XF86Misc extension
is there some one who can help?
thanks