Befor Debian upgrade i updated the hole installation from 1.3.16 to 1.4.6 so i think i never had to import the i-mscp database from the old "hot system" to the new one. All domains i managed always by hand so i have two systems with same domains ad so on.
The Backup system (the new host now) is only for testing and backup. So this system should only work in emergency situations.
I will rename this backup files and check it out.