It would appear that the dewiki replica on toolserver is experiencing significant corruption.
SELECT count(el_to) FROM externallinks JOIN page ON el_from=page_id WHERE page_title='Fabrixx' AND page_namespace=0;
returns 1346 rows
I just loaded the recent dumps locally and same query returns 13 rows, which appears to be the correct result.
This is just an example, the condition occurs on many pages. Either *links rows have not been deleted.. or they have been inserted to the wrong id or some other problem which would cause a relational integrity violation with respect to page table.
I would be surprised if this corruption was limited to externallinks.