INSERT Problem

This is driving me crazy ...

I have a typed dataset that I created using VS2008.  I created an Insert 
statement:

"INSERT INTO x (v1, v2, v3, ..., vN) VALUES (?, ?, ?, ... N?)"

Then I add parameters to the Insert command (OleDbCommand BTW, going into
an 
Access database):

myOldDbCommandInsert.Parameters.Add(new OleDbParameter("columnName", 
OleDbType.DBTimeStamp));
myOldDbCommandInsert.Parameters.Add(new OleDbParameter("columnName2", 
OleDbType.Char));
....
myOldDbCommandInsert.Parameters.Add(new OleDbParameter("columnNameN", 
OleDbType.UnsignedInt));

Now I set my default values:
myOldDbCommandInsert.Parameters["c1"].Value = defaultValue1;
myOldDbCommandInsert.Parameters["c2"].Value = defaultValue2;
....
myOldDbCommandInsert.Parameters["cN"].Value = defaultValueN;

Then I create my data adapter:
OleDbDataAdapter a = new OleDbDataAdapter("SELECT * FROM x", myConn);

Then the dataset:
MyCustomDataSet ds = new MyCustomDataSet();
a.Fill(ds.MyCustomTable);

So far, everything has worked fine up until this point.  So now, I simply 
want to add rows to MyCustomTable:
SomeLoopWith5ValuesOrWhatever
{
  MyCustomDataSet.MyCustomRowA r = (cast) 
MyCustomDataSet.MyCustomTable.NewRow();
  r.v1 = x;
  r.v2 = y;
  r.v3 = z;
  r.nN = N;
  myDataSet.myDataTable.Rows.Add(r);
}

Stepping through the debugger, that appears to do exactly what I expect. 
I 
can see that the table gets the new rows, and they have the correct
values.

However, when I do the following:
myDataAdapter.Update(myDataSet, "NameOfCorrectTable");

The correct number of rows are added to the correct table, but they do not

have the new values?!!  They are keeping the default values that I set 
earlier in my code.  Why is my INSERT statement using these default
values?

It's been a while since I messed with database stuff.
Thanks.