The Stellent code that handles extracting content from the files in Connections , relies on an old version of .

It relies on, while for instance on SLES 12, this is replaced with

It may not be immediately apparent that this is the problem.

If you use , you get a java error, which can throw you off. So use the “exporter” directly, when in doubt.
Check this older blog post, that is about the same problem (but then in Sametime). Installation of Sametime Meeting Server

It also explains how to verify your search indexing settings.