X11 won't start anymore!

Question

Hello,
this is a desperate call: I am at a conference with my MBP, (10.6.7, all updates done). I need Matlab for my presentation, which needs X11.
X11 (and XQuartz) decided that they won't start anymore: the icon bounces in the dock for a while, then sits there without the little light underneath, and X11 is "non responding".
The logs show something like this.
I have googled and searched: similar problems once in a while appear but no posted solution.
I tried:
1) reinstalling XQuartz (I would reinstall X11, but how? I do not have the disks with me, I am away!)
2) from an admin account
3) create a new account.
4) repair permissions.
5) reinstall the font update from Apple that was recently issued.
HELP PLEASE!!!
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]     X11.app: DISPLAY ("/tmp/launch-bHvQen/org.macosforge.xquartz:0") does not match our id ("org.x"), unsetting.
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]     X11.app: main(): argc=2
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]      argv[0] = /Applications/Utilities/X11.app/Contents/MacOS/X11.bin
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]      argv[1] = -psn_0_278596
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]     Waiting for startup parameters via Mach IPC.
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]     X11.app: Could not connect to server (DISPLAY is not set). Starting X server.
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]     X11.app: Launching /usr/X11/bin/startx:
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]      argv[0] = /bin/sh
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]      argv[1] = -c
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]      argv[2] = /usr/X11/bin/startx
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]     font_cache: Scanning user font directories to generate X11 font caches
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]     font_cache: Updating FC cache
11-05-16 5:02:01 PM     org.x.privileged_startx[20781]     font_cache: Scanning system font directories to generate X11 font caches
11-05-16 5:02:01 PM     defaults[20791]
The domain/default pair of (org.x.X11, dpi) does not exist
11-05-16 5:02:01 PM     [0x0-0x44044].org.x.X11[20759]     Couldn't create cookie
11-05-16 5:02:02 PM     org.x.privileged_startx[20781]     font_cache: Updating FC cache
11-05-16 5:02:04 PM     [0x0-0x44044].org.x.X11[20759]     font_cache: Done
11-05-16 5:02:04 PM     org.x.privileged_startx[20781]     font_cache: Done

Answer 1

Here is the solution: there was nothing wrong with x11 per se!
The problem was that about 30 files in /usr/bin (like gzip, egrep, hexdump etc) had been hosed (they had 0 file size).  The puzzling messages was due to the fact that startx uses hexdump, which was simply silently doing nothing (since it had 0 size!).
I do not know what or when these files were zeroed: I suspect a recent OSX update which did not complete and I had to forcefully reboot.
I have fixed it enough to work (copying those files from another mac), but who knows what else lurks beneath the surface of apparent serenity!
I am actually surprised that the whole system did not stop functioning completely.
MORALE: if something looks strange in the logs with x11 or other apps, check the file sizes  in your /usr/bin, you may be surprised too!