Here is some maybe more useful output :
~ yves$ /Applications/MacPorts/X11.app/Contents/MacOS/X11
X11.app: main(): argc=1
argv[0] = /Applications/MacPorts/X11.app/Contents/MacOS/X11.bin
Waiting for startup parameters via Mach IPC.
X11.app: Could not connect to server (DISPLAY is not set). Starting X server.
X11.app: Launching /opt/local/bin/startx:
argv[0] = /bin/sh
argv[1] = -c
argv[2] = /opt/local/bin/startx
font_cache: Scanning user font directories to generate X11 font caches
bootstrap_look_up(): Unknown service name
font_cache: Updating FC cache
xauth: creating new authority file /Users/yves/.serverauth.92814
X11.app: do_start_x11_server(): argc=6
argv[0] = /opt/local/bin/X
argv[1] = :4
argv[2] = -nolisten
argv[3] = tcp
argv[4] = -auth
argv[5] = /Users/yves/.serverauth.92814
2009-02-01 21:01:27.932 X11.bin[92803:717] Could not connect the action apps_table_cancel: to target of class X11Controller
Xquartz starting:
X.Org X Server 1.4.2-apple32
Build Date: 20090201
(EE) XKB: Couldn't open rules file /opt/local/share/X11/xkb/rules/base
(EE) XKB: Couldn't open rules file /opt/local/share/X11/xkb/rules/base
Could not init font path element /opt/local/share/fonts/misc/, removing from list!
Could not init font path element /opt/local/share/fonts/TTF/, removing from list!
Could not init font path element /opt/local/share/fonts/OTF, removing from list!
Could not init font path element /opt/local/share/fonts/Type1/, removing from list!
Could not init font path element /opt/local/share/fonts/100dpi/, removing from list!
Could not init font path element /opt/local/share/fonts/75dpi/, removing from list!
Could not init font path element /Library/Fonts, removing from list!
Could not init font path element /System/Library/Fonts, removing from list!
Fatal server error:
could not open default font 'fixed'
AbortDDX
Quitting Xquartz...
Xquartz: start_x11_server: (ipc/mig) server died
Gandalf:~ yves$ giving up.
xinit: Connection refused (errno 61): unable to connect to X server
xinit: No such process (errno 3): Server error.
font_cache: Done
