gnome starter

[io]

On a MacBookPro I installed the bundle named gnome in the port list.
All OK. Then I considered the article GNOME on the MacPorts HOME.
bash uses profile files, so that I made the following shell file named gnome:
export XDG_DATA_DIRS=/opt/local/share:$XDG_DATA_DIRS
export XDG_DATA_HOME=/opt/local/share:$XDG_DATA_HOME
export XDG_CONFIG_DIRS=/opt/local/etc/xdg:$XDG_CONFIG_DIRS
export ESPEAKER=localhost:$ESPEAKER
cd /opt/local/bin
./metacity &
./gnome-session &
Then, I started X.app and XTerminal,
then I started the file gnome above.
XTerminal replied as follows and stalled:
bash-3.2$ ./gnome
bash-3.2$ Failed to start message bus: launch_msg("CheckIn") IPC failure: Operation not permitted

Xlib:  extension "RANDR" missing on display "/tmp/launch-XJRq02/org.x:0".
EOF in dbus-launch reading address from bus daemon
Avviso del window manager: Lo schermo 0 sul display «/tmp/launch-XJRq02/org.x:0» ha già un window manager
(italian wording means 'Screen 0 on display etc. has yet a window manager)
I know my question is surely a very stupid one, but I hope that someone has the patience to explain my error.