WordPress Domainchanging

Hi everybody! I have troubles by moving my wordpress MU blog to a different domain with the same hoster.
my domain is http://zukunftderkommunikation.com

I did try everything possible now and i am getting quiet desperate now.
Im not new to werdpress and am just getting quick into mySQL.

Following steps i’ve done already:
*Backup Database
*Copy wordpress the wished directory
*changing all links in my database from http://oldurl.com to http://newurl.com
changing the wp-config.php home and siteurl to http://newurl.com
This didn’t work. instead i have some broken links now and can’t
access the network manager any more. So i backuped mySQL
-back to normal. -Site is still redirecting to http://oldurl.com

than i tried define(‘RELOCATE’, true); – no change.

and i am missing the option at the admin section to change the url inside the backend (settings -> General -> Change url)

than i tryed with a new database & user.
Importing the backuped database with the changed links from “oldurl.com” to “newurl.com”

Thanks in advance for your help!!