.htaccess Question

Greetings,

I currently have wordpress installed on two servers that are load balances. The two wordpress instances run great.

The problem I’m having is that

when I use http://www.pens.com/blog I get a 404 error
When I use http://www.pens.com/blog/ it works fine

Here is my .htaccess. If I want the url without the trailing slash to work is this the right configuration? What if I want them both to work?

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /blog/
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /blog/index.php [L]
</IfModule>

# END WordPress

Thanks and regards,

Wade