Avatar rewrite rule problem

I've installed Avatar plugin, but i'm having problem with the rewrite rule.
if I place it in the htaccess activation link don't work. if i remove it activation link work.

this is the .htaccess i'm using :

RewriteEngine On
RewriteBase /

#uploaded files
RewriteRule ^(.*/)?files/$ index.php [L]
RewriteRule ^(.*/)?files/(.*) wp-content/blogs.php?file=$2 [L]

RewriteRule ^(.*/)?avatar/(.*) wp-content/avatars.php?file=$2 [L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule . - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-.*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

it's a wrong rules' position ?