Ubuntu Japanese IME/Emacs

set the root password by
sudo passwd root
Give a new root password

specify japanese ubuntu ring,
system->software sources->third-party software
Add the following two locations for feisty (7.04)

deb http://archive.ubuntulinux.jp/ubuntu-ja feisty/
deb http://archive.ubuntulinux.jp/ubuntu-ja feisty-ja/

close->reread
This will give an error because of public key mismatch, but
do not worry.
Install ubuntu-japanases-ring package

system->admin->synaptic package manager
ubuntu-ja-keyring
Apply->ok
This will download japanese packages and install.

To set up IME, first install Japanese language support by,
admin->language package

Now restart (logout X) and log in again, try
Ctrl+Space

If this does not trigger scim, then you need to add the following
to Xsession.d,

sudo touch /etc/X11/Xsession.d/74custom-scim_startup
sudo chmod 646 /etc/X11/Xsession.d/74custom-scim_startup
echo 'export XMODIFIERS="@im=SCIM"' >> /etc/X11/Xsession.d/74custom-scim_startup
echo 'export GTK_IM_MODULE="scim"' >> /etc/X11/Xsession.d/74custom-scim_startup
echo 'export XIM_PROGRAM="scim -d"' >> /etc/X11/Xsession.d/74custom-scim_startup
echo 'export QT_IM_MODULE="scim"' >> /etc/X11/Xsession.d/74custom-scim_startup
sudo chmod 644 /etc/X11/Xsession.d/74custom-scim_startup

You need to re-log-in to make the changes effective.
Now you can inset Japanese.