Beta4: CameraSpawnPoint cannot be added to a mission?

I thought maybe this was due to my upgrading our codebase to beta4 but I see this even in the unmodified beta4 code when I try to add a CameraSpawnPoint in the world editor:

Set::add: Object "" doesn't exist
tools/worldEditor/scripts/editors/creator.ed.cs (149): Unable to find object: '' attempting to call function 'getTransform'
tools/worldEditor/scripts/editors/creator.ed.cs (149): Unable to find object: '' attempting to call function 'setTransform'
1: Unable to instantiate non-conobject class CameraSpawnPoint.