https://github.com/b13/t3ext-dam_falmigration/blob/master/Classes/Controller/DamMigrationCommandController.php
on line 43 there is a hard reference to uid 1
public function migrateDamRecordsToStorageCommand($storageUid = 1, $recordLimit = 999999)
When the uid in your TYPO3 installation have a other id you get no usefull information in the backend module.