Dataprep: Convert Actors fails

Upon import to Unreal using Dataprep I try to replace StaticMeshActors with a custom Actor that uses ProceduralMeshComponents. I try to use the “Convert Actors” node to do so, but I get error messages when I execute the Dataprep Asset:

“ConvertActorWith … is not in an editor world. The actor will be skipped.”

Minimal Setup in Dataprep:

http://data.raumgleiter.com/SG_UE_TMP/dataprep.png

Event that calls my converter:

http://data.raumgleiter.com/SG_UE_TMP/event.png

The failing part of the converter:

http://data.raumgleiter.com/SG_UE_TMP/replace.png

The error message

http://data.raumgleiter.com/SG_UE_TMP/errors.png