Well it seems it was only a dns issue and after I flushed the dns and rebooted my PC it all worked really fine!
Now I am able to share post from one blog to the other with a plugin called diamond multisite.
One thing that I had to do and its not very clearly mentioned on multisites is that you must have your site on the root dir of your server or else it wont work correctly.
So I had to replace my main domain on my webhost to the domain I need WP Multisite.
@sue: the correct files for you to edit are .htaccess and wp-config.php, you dont need to edit config.sys.
If wp-config is not correctly configured then yes you will run into issues.
Cheers
Nuno
