Multisite sub-blog pictures won't import/broken links

I have a wordpress multisite installed on a (domaine.net). I’m building websites here (domain.net/site1) or (domain.net/site2).

I have .htaccess looks like this:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

# uploaded files
RewriteRule ^files/(.+) wp-includes/ms-files.php?file=$1 [L]

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

I think the problem is where my (domain.net folder is installed) In my cpanel when I access my files I click on the (WWW)/then I click on (domain.net)/ is that the problem? because it’s not in the root folder?

Problem is I can use the main “domain.net” without any problems. I cannot add any images to the “domain.net/site1 or domain.net/site2”

The images appear as broken links or return a 404 error when I enter their URL manually.

Image URL: http://boulos.net/quebec-insurance-investment-blog/files/2013/05/header-blog.jpg

Permalinl: http://boulos.net/quebec-insurance-investment-blog/?attachment_id=61

Thanks to all who answer!! If you need any more information please ask! 🙂