ZCatalog: zcat_data empty, reindexing fails

Hello,

I am trying to implement TextIndexNG3 and PDF indexing and ended up with a problem.

System: ZMS 2.11.4-02, Zope 2.10.11, PYTHON: 2.4.6, Language: German (ger), TextIndexNG3 3.2.2

Catalog-ID: catalog_ger
Index: zcat_data (TextIndexNG3) 
Index: zcat_text (ZCTextIndex)

Problem: zcat_data is empty, reindexing does not work (zcat_text is ok and searchable)

If I add an index "zcat_data_ger" (via manage_catalogIndexes by Zope), PDF file contents get indexed there and are searchable via ZMS. 

Reindexing via ZMS (System-Maintenance-Catalog: Reindex) removes the manually created zcat_data_ger and replaces it with an empty zcat_data.

Is this a bug in ZMS, Zope or TextIndexNG3? 

By the way: On an older ZMS, TextIndexNG3 works without problems (with a different naming scheme):

ZMS 2.9.4-14
Zope 2.9.2
PYTHON: 2.4.6 
TextIndexNG3 3.1.16
Catalog-ID: catalog
Index: zcat_data_ger (TextIndexNG3)
Index: zcat_text_ger (TextIndex)

Kind regards,

Hermann Husen