Subdirectory domain mapping

Hello all,

I have successfully set up WordPress Multi-site on my server. I have faithfully followed every single step that was listed by WordPress.

I am using the subdirectory install and everything is fine as of now except the domain mapping part.

mydomain.com/site1
mydomain.com/site2
mydomain.com/site3
mydomain.com/site4
.
.
.
works fine!

Mapping http://www.xyz.com to mydomain.com/site1 throws a “403 Forbidden
You don’t have permission to access / on this server.” error.

I have followed this tutorial (and also installed that plugin):
http://ottopress.com/2010/wordpress-3-0-multisite-domain-mapping-tutorial/

Something to do with .htaccess? Here’s my htaccess:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]

ErrorDocument 404 /index.php?error=404

RewriteRule ^login$ /wp-login.php [L]
RewriteRule ^signup$ /wp-signup.php [L]
RewriteRule ^register$ /wp-register.php [L]

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ – [L]
RewriteRule ^[_0-9a-zA-Z-]+/(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^[_0-9a-zA-Z-]+/(.*\.php)$ $1 [L]
RewriteRule . index.php [L]

I have set up TWO A records on my domain manager for xyz.com to point to my server’s IP address.

Address:xyz.com | Type:A RECORD | Points to: server IP
Address:www.xyz.com | Type:A RECORD | Points to: server IP

And still, it throws a 403 error on me. Any help would be much appreciated.