Currently it proceeds through the import and only dies when it tries to write files. We can do a better job of communicating what the error is here
PR: https://pagure.io/koji/pull-request/631
Commit 21fefc4c fixes this issue
Metadata Update from @tkopecek: - Issue set to the milestone: 1.15
This issue has been migrated to Fedora Forge: https://forge.fedoraproject.org/koji/koji/issues/425
Please continue any further discussion there.