indexing pdf errors

"Henk L." <[email protected]> Mon, 29 Mar 2021 10:10:39 +0200

Newsgroups	gmane.comp.search.xapian.general
Message-ID	<[email protected]>

I have indexed pdf's with omindex. In this batch not all went well,
though the files got indexed. I get errors:

Syntax Warning: Couldn't link the profiles
Syntax Warning: Can't create transform

These pdf's are the output of a scan and ocr process. So they contain
text.  

Is there a way I can find out what happened?