Comment 2 for bug 209476

the patch: 00_xdg_data_dirs.patch

touches the line which may be the problem:

diff -Nur xfce4-utils-4.4.1/scripts/startxfce4.in xfce4-utils-4.4.1.new/scripts/startxfce4.in
--- xfce4-utils-4.4.1/scripts/startxfce4.in 2007-04-02 07:34:54.000000000 +0200
+++ xfce4-utils-4.4.1.new/scripts/startxfce4.in 2007-10-04 23:16:56.000000000 +0200
@@ -28,9 +28,9 @@

 if test "x$XDG_DATA_DIRS" = "x"
 then
- XDG_DATA_DIRS="usr/local/share:/usr/share:/@datadir@"
+ XDG_DATA_DIRS="etc/xdg/xubuntu:usr/local/share:/usr/share"
 else
- XDG_DATA_DIRS="$XDG_DATA_DIRS:@datadir@"
+ XDG_DATA_DIRS="etc/xdg/xubuntu:$XDG_DATA_DIRS:@datadir@"
 fi
 export XDG_DATA_DIRS

OP reports that the missing "/" at the start of the variable is causing grief. Looks like an upstream bug on the first removed line, which has been propagated further by the Ubuntu changes.