Data Migration Tool -> Failure

[cadtec]

Hello! How can I Re-Import an ARB-File? If try to migrate an ARB-File a second one, I receive the following error: An active repository that matches the one in the backup file already exist. {890DB3EA-71FA-49B7-8E80-65E0AA9BF812}
What I must do, that I can re-import again?
Best regards,
CADTEC