Hello, all.
For (yet) unknown reasons, last complete dump files (pages-meta-history.xml) in some languages are flawed. Certain revision items are missing info about rev_user. Even though there are only 3 or 4 of that kind, this is enough to mess up either the parsing process or the later SQL load into the DB.
So far, the last 3 dumps of DE Wikipedia and 20090603 from FR Wikipedia have presented this error.
I have updated both WikiXRay parsers: http://meta.wikimedia.org/wiki/WikiXRay_parser http://meta.wikimedia.org/wiki/WikiXRay_parser_research
They now probe whether the parsed revision item is complete or not, before creating the SQL. If it's flawed, its omitted and logged into an error file for later inspection.
Regards,
Felipe.