301 redirect error on DLE

[__Doc_]

RewriteCond %{HTTP_HOST} !^www\.[a-z-]+\.[a-z]{2,6} [NC]
RewriteCond %{HTTP_HOST} ([a-z-]+\.[a-z]{2,6})$ [NC]
RewriteRule ^/(.*)$ http://%1/$1 [R=301,L]

?
im not 100% on what you want to do

or remove www

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

and always start your htacess with

Options +FollowSymLinks
RewriteEngine On
RewriteBase /