>Hi Tomasz. I already checked the source database for duplicated entries,
>and found none, but i did not tried to verify the database with gfix.

Exactly how did you check it for duplicate entries? The point is that if there's a problem with an index or key, then doing

SELECT MyIndexedField, count(*)
FROM MyTable
GROUP BY 1
HAVING count(*) > 1

will use the index/key and not discover the duplicate entry, whereas

SELECT MyIndexedField+0, count(*)
FROM MyTable
GROUP BY 1
HAVING count(*) > 1

cannot use the index and will find such duplicates.

HTH,
Set