I am not familiar with TopLink, but let me ask you this. For your Inserted record, are there relationships to other tables, like this is a Many side in a One-To-Many? Or is it a straight single table, no FK relationships insert?
So, if it is, then what this means is that it is trying to insert a record on the many side, where there is no record (Parent record) in the one side. So you can't have a child without a parent.
Mark