>Is it possible that you are trying to insert a null where a field does not allow nulls? Or perhaps you are trying to update the child before the parent (a foreign key issue)?
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>Have you trie checking the datatable's hasErrors property in the dataset and then invoking the GetErrors method on each of the tables with errors. It should return a collection of datarows. Look at the rowError property on each. You could try setting .enableconstraints on the dataset to false before the fill so you can watch the errors.

The command is a SQL select. Will what you juste wrote still applicable in such a situation?

I also checked the data. The SQL Select is a very simple one. It includes one INNER JOIN. However, in that INNER JOIN, I can see in the table of the joined table that there are multiple records having the same INNER JOIN key. This is probably where it is not happy about it. However, this has worked well in VFP. It seems SQL Server detects something that VFP was not capable of. I verified with the client to know if it was normal to have the joined table to have multiple records on the same key.