You have a typo... or at least don't have the same code he has... his file
is in the /system directory... Here's the configs I've used in the past
that have worked for me when public/system/maintenance.html exists...
# Check for maintenance file and redirect all requests
# ( this is for use with Capistrano's disable_web task )
RewriteCond %{DOCUMENT_ROOT}/system/maintenance.html -f
RewriteCond %{SCRIPT_FILENAME} !maintenance.html
RewriteRule ^.*$ /system/maintenance.html [L]
Yeah, I have mine in public/maintenance.html, I did try moving it to
system under he superstition that maybe that mattered, but it did
not. The really confusing thing is that the rewrite log says
"comparing to /^.*$/ (ie everything), and then passing thru, come on,
it's gotta match !