Duplicate records entered on update

OK, I've been trying to figure this out for almost 2 weeks and I can't seem to perfrom a serach that identifies anyone else having the same problem...  I have a small access database I created to hold daily observations of an instrument's performance and state (in the laboratory)...  I was playing with data I've logged in the book for years and I thought I might be making some connections, so I thought having an automated record which could be graphed would be kinda cool.  Like to keep my programming skills fresh too.  When I leaned ADO.NET it was with VS2002, so I was playing with the VS2005 tools and I just dragged a BindingSource onto my MainForm, then used it to make a deataset and annotated the datatable as the datamember.  See  here and here.  All good.  I can call the Adapter.Update() method when adding a new row without any problem.  I have a form which lets me edit and/or delete records (all works fine on the in-memory dataset) and a form which graphs the data.  When I close out my app, I want the access database file to be updated accordingly.  Here's where havoc insues.  I was using the following code:

[CODE]
        private void MainForm_FormClosed(object sender, FormClosedEventArgs e)
        {
            if (this.iRMSLogDataSet.HasChanges())
            {
                DataSet dsChanges = iRMSLogDataSet.GetChanges();
                this.iRMSLogTableAdapter.Connection.Open();
                this.iRMSLogTableAdapter.Update((iRMSLogDataSet)dsChanges);
                this.iRMSLogDataSet.AcceptChanges();
                this.iRMSLogTableAdapter.Connection.Close();
            }
        }
[/CODE]

It creates duplicate records in the main database file which are in the in-memory DataSet upon closing the app!  So if I delete records 6-8, records 1-5 and 9-XX will all be duplicated in my access database file.  I can't for the life of me figure out why???  I know I must be missing something simple, but in weeks of searching I can't find someone who's had this same problem and has a solution....  Any help would be most appreciated!

Tom