Getting Data From Dataset Back Into Database

I'm new at this so I apologize in advance for my ignorance.

I'm creating a website that collects dates in a calendar control (from Peter Blum). When the page containing the control loads it populates the calendar with dates from the database (that have previously been selected by the user). The user then can delete existing dates and/or add new dates.

I create a dataset when the page loads and use it to populate the calendar. When the user finishes adding and deleting dates in the calendar control I delete the original dates from the dataset and then write the new dates to the dataset. I then give execute the data adapter update command to load the contents of the dataset back into the database. This command involves using parameterized queries. For example the Insert command is:

Dim cmdInsert As SqlCommand = New SqlCommand("INSERT INTO Requests VALUES(@fkPlayerIDNumber, @RequestDate, @PostDate, @fkGroupID)", conn)

cmdInsert.Parameters.Add(New SqlParameter("@fkPlayerIDNumber", SqlDbType.Int))

cmdInsert.Parameters.Add(New SqlParameter("@RequestDate", SqlDbType.DateTime))

cmdInsert.Parameters.Add(New SqlParameter("@PostDate", SqlDbType.DateTime))

cmdInsert.Parameters.Add(New SqlParameter("@fkGroupID", SqlDbType.Int))

da.InsertCommand = cmdInsert

The update command is:

da.Update(ds, "Requests")

When I run the program I get the following error:

Parameterized Query '(@fkPlayerIDNumber int,@RequestDate datetime,@PostDate datetime,' expects parameter @fkPlayerIDNumber, which was not supplied.

I've used debug print to establish that the table in the dataset contains what it should.

I would be more than grateful for any suggestions.