mod-rewrite to ignore the subdomain

I'm using a mod-rewrite for pretty URLs, meant to run on the domain root. Working fine but now I'm trying to make it run on a subdomain and it keeps giving "500 Internal Server Error".

The subdomain automatically redirects to the folder with that name o开发者_如何转开发n my hosting account (sub.domain.com shows the content of domain.com/sub/). Does it fail because this request is already being mod-rewritten automatically or can I simply change something in the htaccess to address the subdomain instead?

Options +FollowSymLinks
IndexIgnore */*
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . index.php

Contact your ISP and check if they are setting the DocumentRoot for the sub domains to the /domain/sub/ directory (it's probable) or alternatively using an internal RewriteRule to direct traffic to that directory (you can see if there's an external rewrite / redirect in place via Chrome or Firefox + firebug, use the developer tools to check the response header, on the network Tab). If they have set the document root you will need to copy or symbolically link ALL the files you want accessible via the sub-domain, to the /domain.com/sub/ directory e.g. the .htaccess, index.php, images, js and css files and sub directories. If they are using an internal rewrite, a quick tweak to your own existing internal rewrite, in the existing .htaccess file, should suffice e.g.

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php  [L]