[XeTeX] I can't find the format file `xelatex.fmt'!

[Mike Maxwell]

...and neither can I.

That's the error msg (on my subject line) when I try to run xelatex. 
There's a file xetex.fmt, in 
~/.texlive2007/texmf-var/web2c/xetex/xetex.fmt, but there's no 
corresponding xelatex.fmt (or the directory it would go into).

There is a Q/A about a missing xelatex.fmt file in the FAQ at 
http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&item_id=xetex_faq#xelatex, 
but that appears to pertain to the Apple installation, not to the Linux 
installation that I'm running.  Specifically, I can't debug the process 
by "use Show Log in the Apple Installer, or View Subprocess Output in 
i-Installer".  Nevertheless, I tried doing what this answer suggests and 
commenting out virtually all the languages except English and 
nohyphenation in my language.dat file, and then re-running 
'/usr/share/bin/x86_64-linux/texconfig init', to no avail.  There's 
still no xelatex.fmt.

BTW, '/usr/share/bin/x86_64-linux/texconfig conf' appears to run OK, 
i.e. there are no obvious error msgs.  And 
'/usr/share/bin/x86_64-linux/texconfig init xelatex' appears to do 
nothing, which I suppose is not a good sign.

(It's unclear whether I'm supposed to run texconfig as root or not. 
I've done it both ways, with no obvious difference, except that 
'texconfig rehash' needs to be run as root.)

There's a variant on this procedure at 
http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&item_id=xetex_fink, 
but again, it seems to pertain to the Apple.  (Is fmtutil just called by 
texconfig?)  At any rate, the command
    fmtutil --enablefmt xelatex
gives the output
    fmtutil: initial config file is `/usr/share/texmf/web2c/fmtutil.cnf'
    fmtutil: configuration file unchanged.
and still no xelatex.fmt file.

What am I doing wrong?  Is there another way to create this elusive 
xelatex/xelatex.fmt file?
-- 
	Mike Maxwell
	maxwell at umiacs.umd.edu
	"Theorists...have merely to lock themselves in a room
	with a blackboard and coffee maker to conduct their business."
	--Bruce A. Schumm, Deep Down Things