.htaccess rewrite rule kills trailing slash auto redirect in parent directory

[agentolivia]

Summary of Problem: The .htaccess rewrite rule in /eventregistration/onlineteachers/ is overriding an "automatic" trailing-slash-adding redirect that is the default server behavior. This has the effect of not redirecting /eventregistration/onlineteachers to /eventregistration/onlineteachers/. A .htaccess rewrite rule in /eventregistration/ has no positive effect, but rather hair-pulling, premature-aging effect.

First, in my httpd.conf (Apache/1.3.29), I have the following (to allow .htaccess files in this directory and subdirectories the ability to use RewriteRules):

<Directory "/var/www/nwrel/eventregistration">
   AllowOverride FileInfo
            </Directory>

Second, in a /eventregistration/onlineteachers/ directory I have an .htaccess file that redirects just about everything to index.php (in order to use Harry Fuecks very cool PathVars class - PHP Anthology, Vol. 1, pg 312ff). The .htaccess looks like this:

RewriteEngine on
            RewriteRule !(\.gif|\.jp?g|\.css|\.php|^images/.*)$ index.php [nocase,last]

All is fine and dandy except for one little annoying thing: the "automatic" redirect that happens when a trailing slash is missing from a URL doesn't happen in the parent directory, "eventregistration". (I don't want a trailing slash redirect in "onlineteachers" but I do want it in "eventregistration," so that "http://www.nwrel.org/eventregistration/onlineteachers" redirects to "http://www.nwrel.org/eventregistration/onlineteachers/" and the .htaccess in "onlineteachers" kicks in)

So I tried to write a rewrite rule in the /eventregistration/ directory's .htaccess file as per the Apache docs suggestion:

RewriteEngine on
            RewriteRule ^onlineteachers$  onlineteachers/ [R]

But all I get is "Bad Request: Your browser sent a request that this server could not understand " in Firefox and a "Page Not Found" error in IE6. Oh so helpful.

I have looked everywhere, but frankly I'm new at .htaccess and mod_rewrite, so maybe I just haven't loooked for the right things. I hope someone here can help.

Thanks a ton.
Amber