Ваш htaccess должен выглядеть примерно так
# Turn on URL rewriting
RewriteEngine On
# Installation directory
RewriteBase /
# Protect hidden files from being viewed
<Files .*>
Order Deny,Allow
Deny From All
</Files>
# Protect application and system files from being viewed
RewriteRule ^(?:application|modules|system)\b.* index.php/$0 [L]
# Allow any files or directories that exist to be displayed directly
RewriteCond ${REQUEST_URI} ^.+$
RewriteCond %{REQUEST_FILENAME} \.(gif|jpe?g|png|pdf)$ [OR]
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d [OR]
RewriteCond %{REQUEST_FILENAME} -l
RewriteRule ^ - [L]
# Rewrite all other URLs to index.php/URL
RewriteCond ${REQUEST_URI} ^!galleries/.*$
RewriteRule .* index.php/$0 [PT]
, что исключает его отправку в механизм маршрутизации.