Document Type Editor throws exception

When starting to edit a document type in the doc type editor, I see and exception in the terminal:

[INFO] [talledLocalContainer] 29.08.2014 12:53:04 WARN http-bio-8080-exec-11 [LinkPickerDialogConfig.getPickerBaseUuid:62] Failed to get UUID of translated base folder, using default instead
[INFO] [talledLocalContainer] javax.jcr.ItemNotFoundException: Root node doesn't have a parent
[INFO] [talledLocalContainer] at org.apache.jackrabbit.core.NodeImpl$6.perform(NodeImpl.java:1750)
[INFO] [talledLocalContainer] at org.apache.jackrabbit.core.NodeImpl$6.perform(NodeImpl.java:1743)
[INFO] [talledLocalContainer] at org.apache.jackrabbit.core.session.SessionState.perform(SessionState.java:216)
[INFO] [talledLocalContainer] at org.apache.jackrabbit.core.ItemImpl.perform(ItemImpl.java:91)

[...]

(Reproduced with the newsdocument type on the 1.09.01 archetype)

Some debugging suggests that the doc type editor creates a copy of the document type's "prototype node", but that copy has a primary type of "nt:unstructured". The LinkPickerDialogConfig goes looking for a parent node of type "hippo:document", but because the prototype node has primary type nt:unstructured, it doesn't find such a parent and eventually bumps into the fact that the root node has no parent.

I suspect the root of the problem is that the copied prototype node has a different primary type than the original prototype node...?