After watching the video on using TreeJoin, I was able to use this in one Dataflow without any problems. However, in a subsequent very similar dataflow, I try using it and while attempting to preview data at the join (or beyond for that matter) I get the message "Object not set to an instance of an object". I can Preview Data on the two items that flow into the join without issue.
Any recommendations where to look for what is causing this problem?
Thanks!
=Carlos