Error activating XKB configuration

Binary package hint: gnome

Using Ubuntu Studio, upgraded to 8.04 today. PC is a notebook VAIO PCG-FR33 (CPU:AMD, RAM:1GB).
The error message is:
Error activating XKB configuration
a bug in libxkavier library
a bug in Xserver(xkbcomp, xmodmap utilities)
Xserver with incompatible libxkbfile implementation

~$ xprop -root | grep XKB
_XKB_RULES_NAMES_BACKUP(STRING) = "xorg", "jp106", "jp,jp", "latin,", "grp:alt_shift_toggle,lv3:ralt_switch,grp_led:scroll"
_XKB_RULES_NAMES(STRING) = "xorg", "jp106", "jp,jp", "latin,", "grp:alt_shift_toggle,lv3:ralt_switch,grp_led:scroll"

:~$ gconftool-2 -R /home/laurel/.gconf/desktop/gnome/peripherals/keyboard/kbd
'/home/laurel/.gconf/desktop/gnome/peripherals/keyboard/kbd' の中にあるエントリの読み込みでエラー: 使用できないキーまたはディレクトリ名です: "/home/laurel/.gconf/desktop/gnome/peripherals/keyboard/kbd": スラッシュ '/' の直後にはピリオド '.' を指定できません

gconf-editor shows:
kbd layouts [jp latin]
model jp106
options
  grp grp:alt_shift_toggle
  lv3 lv3:ralt_switch
  grp_led grp_led:scroll
  grp_led grp_led:num
overrideSettings (checked)

ProblemType: Bug
Architecture: i386
Date: Sat Apr 26 15:45:01 2008
DistroRelease: Ubuntu 8.04
ExecutablePath: /usr/bin/yelp
NonfreeKernelModules: nvidia
Package: yelp 2.22.1-0ubuntu2
PackageArchitecture: i386
ProcEnviron:
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
 LANG=ja_JP.UTF-8
 SHELL=/bin/bash
SourcePackage: yelp
Uname: Linux 2.6.24-16-rt i686