Bonnie, don't say that! I teach C# at my work place and I accidently forgot a minor detail like this. Most instructor try to get the student to learn the fundimentals and details such as these get left. It's not that big of a deal, Bonnie - Take it easy on us. :)
Thom, when adding a new record and before updating try
dataset.tables["yourtable"].Rows[0].BeginEdit()
dataset.tables["yourtable"].Rows[0].EndEdit()
repectively. Rows[0] represents the row you're currently editing.