You don't have permission to access /wp-admin/media-upload.php on this server.

I have a custom plugin that allow users to upload certain file to our server. I call wordpress media uploader from my javascript. Before installing BPS everything seems fine. But after installing BPS, media uploader not showing, the script result error :

Forbidden

You don't have permission to access /wp-admin/media-upload.php on this server.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

I try solution here and include the code below to the .htaccess

# Sentrafile skip/bypass rule
RewriteCond %{REQUEST_URI} ^/wp-content/plugins/sentrafile/ [NC]
RewriteRule . - [S=13]

but still no luck.

Any solution for this?

I just call the default .htaccess to make it work for now. But I think I still want to use BPS. So, solution is still needed.

Thank you..

http://wordpress.org/plugins/bulletproof-security/