Error upgrading: Host may not be null

Hi, didn't find this issue in the history.

I'm trying to upgrade from version 1.2.5 to 2.0.6 according to the manual. Excuted artadmin dump $ARTIFACTORY_HOME from old version and - after a fresh install of 2.0.6 - artadmin import dumpExport --user admin --password password. The error mentioned occurs: Reloading configuration from /java/artifactory-2.0.6/etc/import_artifactory.config.xml
500 : Received uncaugth exception
java.lang.RuntimeException: java.lang.IllegalArgumentException: Host may not be null

Does someone have any clue?

Thanks in advance.