Hey, we ordered Xen not long time ago.
Anyone knows if there is web based admin panel or something like that? Using my registred licence email and password. like http://www.myadress.com/admin.php or like that?
The license credentials are for here at xenforo.com. They are completely unrelated to logging into your own forum. On your own forum, if you don't know what password you set when you installed it, do as Brogan said and use the lost password function. The password to login to your admin control panel is the same as to log in to your forum.