The problem is that I installed first a fresh moodle 2.0.3 and when I got the admin user, i logged out and i copied the moodle folder from the first server to the second one, i changed the config.php and i though that with these settings i would have the two webs servers ready, but they aren't. The second server can't logging with the users created in the first server and i don't know the reason.
Can anybody give me a hand?
I'm going to check the permissions from the dataroot. About the password salting, i copied the same config.php from one to another and i changed the IP address, but both servers have the same salting string. Is that correct??
More or less... same salt and config.php should be actually equal in every node of a Moodle load balancing cluster plus $CFG->reverseproxy appropriate setting: you cannot easily access Moodle using more than one FQDN; it could be the reason of your Moodle session expiring due to the different cookie domain.
BTW, check the permissions and then you'll see if a new issue (FQDN) will come up.