Sysadmin

Probably WPSuperCache blocks access. Try to remove every lines, which contains reference to WPSuperCache.

delete:
#RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

To avoid ms-files.php…
and replace with:

RewriteRule ^([_0-9a-zA-Z-]+/)?blog1/files/(.+) wp-content/blogs.dir/1/files/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?blog2/files/(.+) wp-content/blogs.dir/2/files/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?blog3/files/(.+) wp-content/blogs.dir/3/files/$2 [L]
etc.

or like in my .htaccess files:

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?local-transport/files/(.+) wp-content/blogs.dir/3/files/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?international-transport/files/(.+) wp-content/blogs.dir/4/files/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?buses/files/(.+) wp-content/blogs.dir/5/files/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?rescue-transport/files/(.+) wp-content/blogs.dir/6/files/$2 [L]

Adress looks like http://www.domain.com/myrootblog/local-transport/

in myrootblog is my wp installed in subdirectory (not in root folder)
and local-transport is my second blog name etc.

Hope it will be helpful.

By the way seem like redirecting FollowSymLinks MultiViews sometimes isn’t turned on. I mean this:

<Directory /usr/local/var/www>
Options FollowSymLinks MultiViews
AllowOverride None
Order Allow,Deny
Allow from all
</Directory>

Where it should be:

<Directory /usr/local/var/www>
Options FollowSymLinks MultiViews
AllowOverride All
Order Allow,Deny
Allow from all
</Directory>

in file: httpd.con

Why the hell in WordPress MU they made redirect via .htaccess like this:

domain.com/files/2011/02/file.jpg points to ms-files.php which translates that as domain.com/wp-content/blogs.dir/1/files/2011/02/file.jpg

Seems media uploader uploads files correctly to any folder you want, but there is something wrong with some php files . Maybe functions.php ? I don’t know why, when you are in subfolder blog admin panel in media tab , all thumbs are broken and the url file looks like http://www.domain.com/mainblog/blogno2/files/image.jpg and should looks like http://www.domain.com/mainblog/wp-content/uploads or eventually http://www.domain.com/mainblog/wp-content/blogs.dir/%BLOG_ID%/files/ or http://www.domain.com/mainblog/wp-content/blogs.dir//$blog_id/files

I know everywhere write I should install WP MU in root directory. But what if it isn’t possible and I just have to install WP MU in subdirectory? Which files should be edited and corrected?

Maybe in wp-config.php should I paste something like this?
define( ‘UPLOADBLOGSDIR’, $blog_id.’/files/’ );