Multipress - WP Admin Infinite Loop

Hey guys, another query on multipress, seems that i'm having a problem with accessing wp-admin from sites created along with the members that create them.

On a browser I'm presented with this:-

This webpage has a redirect loop

My Config is set up like this

/* Multisite */
define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', false);
define('DOMAIN_CURRENT_SITE', '');
define('PATH_CURRENT_SITE', '/setupfolder/');
define('SITE_ID_CURRENT_SITE', 1);
define('BLOG_ID_CURRENT_SITE', 1);
define('WP_DEFAULT_THEME', 'theme-folder-name');

And my .htaccess is set up like so:-

RewriteEngine On
RewriteBase /setupfolder/
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).*) folder/to/site/setupfolder/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ folder/to/site/setupfolder/$2 [L]
RewriteRule . index.php [L]

Any help would be greatly appreciated, i've looked all over for a solution, tried numerous things and i'm stumped

Thank you

Kind Regards