[Mediawiki-l] Changing system messages through language.php

[April]

I need to change a number of system messages.  I'm running dozens of 
wikis that all need the same changes, so I'm hoping to avoid changing 
the messages through the system messages web interface.

I found instructions for doing this at 
http://meta.wikimedia.org/wiki/MediaWiki_localization but neither method 
is working.

Here's a rundown of what I've done, which might help others diagnose my 
problem:

I edited language.php to display different messages.
I uploaded language.php to overwrite the old language.php in the 
languages folder.
I added $wgUseDatabaseMessages = false; to localsettings.php.
Nothing changed.  I refreshed, tried logging out and in and changing my 
skin in preferences, trying to fix it if it were a cache problem.  I'm 
not yet running cache software (memcache, etc.).

So I removed the $wgUseDatabaseMessages = false; from localsettings.php.
I ran the rebuildMessages.php script from the command line, and it 
displayed a message saying it was rebuilding the namespace.
Nothing changed even after refresh.  Again I tried changing my skin in 
preferences in case it was a cache problem.  I also tried looking from a 
different computer which hasn't seen the site for a few days.

If anyone who understands how language.php works could help me out I'd 
be very grateful.