Smart search indexer fails with "Unable to set as revision as current revision on post"

Hi,

I have version 5.0.19 of easyblog and I want to use smart search.
For that, I installed the smart search plugin and logged into a SSH session.
Then I run the

php finder_indexer.php

command.

It stops after a first batch with the error: "UNABLE TO SET AS REVISION AS CURRENT REVISION ON POST"

This exact problem was fixed in this thread, but I don't have enough info from that thread to fix my own issue. (http://stackideas.com/forums/cannot-access-blogs-at-all-error-400-unable-to-set-as-revision-as-current-revision-on-post)

The exact output from the SSH client:

Smart Search INDEXER

============================

Starting Indexer

Setting up Smart Search plugins

Setup 1041 items in 0.443 seconds.

 * Processed batch 1 in 12.032 seconds.

Unable to set as revision as current revision on post.

Can you help me?

Thanks,

Roel