.htaccess and addon problem

[bentong]

Options +Indexes
Options +FollowSymlinks
RewriteEngine on
RewriteBase /

RewriteCond %{HTTP_HOST} !^www\.maindomain\.com [NC]
RewriteRule ^(.*)$ http://www.maindomain.com/$1 [L,R=301]

I have this 301 redirection on public_html for my main domain/acct however when I tried adding an addon, I always redirected to maindomain.com/addon when I type addon.com on the address bar.

 

[weblord]

what if you remove the .htaccess file or disable it first by renaming it? what happens then?