thank you VentureMaked
i change like what you said but i face same error
this is my .htaccess file
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RewriteEngine On
RewriteBase /
#uploaded files
RewriteRule ^(.*/)?files/$ index.php [L]
RewriteCond %{REQUEST_URI} !.*wp-content/plugins.*
RewriteRule ^(.*/)?files/(.*) wp-content/blogs.php?file=$2 [L]
# add a trailing slash to /wp-admin
RewriteCond %{REQUEST_URI} ^.*/wp-admin$
RewriteRule ^(.+)$ $1/ [R=301,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]
<IfModule mod_security.c>
<Files async-upload.php>
SecFilterEngine Off
SecFilterScanPOST Off
</Files>
</IfModule>
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and i change the name of file from htaccess.dist to .htaccess also i give it CHMOD 777
because i get this warning
_________
Warning! .htaccess already exists.
A file with the name '.htaccess' already exists in this directory and I cannot write to it. Please ftp to the server and delete this file from this directory!
Offending file: /home/xxxx/public_html/blogs/.htaccess
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but no way
any thing ???!!!