xfce4 -4.2.3-3 fc5 won't startup on fedora

[sean]

I've installed xfce on fc5.  X appears to start, and the blue fedora 
bubble logo shows up. There's a panel centered at the bottom. Clicking 
any item on the panel, or even hovering, generates a crash box, which 
regenerates the panel.

Here are the messages from the console:

.............
(==) Using config file: "/etc/X11/xorg.conf"

/usr/bin/startxfce4: X server already running on display :0
Agent pid 4100
which: no xfce4-session in 
(/usr/kerberos/sbin:/usr/kerberos/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/usr/X11R6/bin:/usr/NX/bin:/root/bin)

(xfce-mcs-manager:4103): libxfce4mcs-CRITICAL **: 
mcs_manager_add_channel_from_file: assertion `filename != NULL && strlen 
(filename) > 0' failed
/etc/xdg/xfce4/xinitrc: line 106:  4105 Segmentation fault      xfwm4 
--daemon
** Message: Cannot connect to session manager
/etc/xdg/xfce4/xinitrc: line 123:  4108 Segmentation fault      xfcalendar
/etc/xdg/xfce4/xinitrc: line 123:  4110 Segmentation fault      $panel


No errors in Xorg.0.log.

I assume the root cause is the the xfce-mcs-manager error. It seems to 
be looking for something it can't find.

Any help appreciated.

sean