wordpress 3.5 upgrade problems images missing

Hi, I have an issue with images not being displayed after I did the 3.5 upgrade.
I have a number of sites on my multisite installation and none of them are displaying images in the front end or back end.
I have read all the posts I can find on the forum regarding this problem.

I have tried all the usual things one must do turning off themes and plugins, with no luck.

In one of the posts someone else seemed to be having exactly the same problem. In that post it is mentioned that there is/was a problem with the .htaccess file. I have tried the solution from that post (https://www.ads-software.com/support/topic/wordpress-35-upgrade-multisite-issues/page/2?replies=35) but to no avail.

Is there any chance you could have a look at my .htaccess file to see if I have something screwy with my .htaccess file.
this is my file:

suPHP_ConfigPath /home/clixbits/
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]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(wp-(content|admin|includes).*) wp/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ wp/$2 [L]
RewriteRule . index.php [L]
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
RewriteRule ^files/(.+) wp-includes/ms-files.php?file=$1 [L]
</IfModule>

# END WordPress

Thanks for any help.