INSERT into Access DB using Windows Forms not working but not throwing an error

I'm trying to insert user entered data into a Windows Form into an Access DB. In the form I use a text box, combo boxes that are populated by lookup tables in the db, and 2 dateTimePickers. Through my own debugging attempts, I think I've narrowed it down to the dateTimePickers but I'm not 100% sure. I'm not getting any error, no exceptions are being caught and the "Success Message" is shown after I execute the query but nothing is added to the database.

This is the method call from the form:

try
{
    //get values from form
    int updatedRow;
    int ethnicityID = Convert.ToInt32(comboBoxEthnicity.SelectedValue);
    int genderID = Convert.ToInt32(comboBoxGender.SelectedValue);
    int raceID = Convert.ToInt32(comboBoxRace.SelectedValue);
    DateTime dob = dateTimePickerDoB.Value;
    DateTime dateOfConsent = dateTimePickerDateOfConsent.Value;
    int hhpid = Convert.ToInt32(textBoxHHPID.Text);

    //add new patient to db
    updatedRow = TrialDB.writePatient(dataSetTrial, ethnicityID, genderID, raceID, dob, dateOfConsent, hhpid);
    //success message, number of new patients added
    MessageBox.Show(updatedRow.ToString() + " patient record has been added to the database.");
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
}

And here is the method from the middle tier:

public static int writePatient(DataSetTrial dataSetTrial, int ethnicityID, int genderID, int raceID, DateTime dob, DateTime dateOfConsent, int hhpid)
{
    int addedRow;
    OleDbDataAdapter writePatientAdapter;

    try
    {
    //configure adapter
    writePatientAdapter = new OleDbDataAdapter();

    //insert command
    writePatientAdapter.InsertCommand = new OleDbCommand();
    writePatientAdapter.InsertCommand.CommandText = "INSERT INTO Patient (EthnicityID,GenderID,RaceID,DateOfBirth, " +
                                                                " DateOfConsent,HomeHealthPatientID) " +
                                                                " VALUES (?,?,?,?,?,?)";

     writePatientAdapter.InsertCommand.Connection = new     OleDbConnection(connectString);

     //insert command paramaters
     writePatientAdapter.InsertCommand.Parameters.Add("@EthnicityID", OleDbType.Integer);
     writePatientAdapter.InsertCommand.Parameters["@EthnicityID"].Value = ethnicityID; 


     writePatientAdapter.InsertCommand.Parameters.Add("@GenderID", OleDbType.Integer);
     writePatientAdapter.InsertCommand.Parameters["@GenderID"].Value = genderID; 

     writePatientAdapter.InsertCommand.Parameters.Add("@RaceID", OleDbType.Integer);
     writePatientAdapter.InsertCommand.Parameters["@RaceID"].Value = raceID;

     writePatientAdapter.InsertCommand.Parameters.Add("@DateOfBirth", OleDbType.Date);
     writePatientAdapter.InsertCommand.Parameters["@DateOfBirth"].Value = dob; 

     writePatientAdapter.InsertCommand.Parameters.Add("@DateOfConsent", OleDbType.Date);
     writePatientAdapter.InsertCommand.Parameters["@DateOfConsent"].Value = dateOfConsent; 

     writePatientAdapter.InsertCommand.Parameters.Add("@HomeHealthPatientID", OleDbType.Integer);
     writePatientAdapter.InsertCommand.Parameters["@HomeHealthPatientID"].Value = hhpid; 

    writePatientAdapter.InsertCommand.Connection.Open();

     addedRow = writePatientAdapter.Update(dataSetTrial, "Patient");

     }
     catch (Exception)
     {
         throw new ApplicationException(dbOrDeErrorMsg);
     }

         writePatientAdapter.InsertCommand.Connection.Close();

         return addedRow;
}

When I add the DateTime variables to my watch list in debug mode it has trouble evaluating the leading { in the format from the dateTimePicker. That's why I'm thinking it's the DateTime causing me trouble. I tried the INSERT statement in the DB directly and it worked, but I can't account for the date formatting when I'm typing it in by hand. The web shows a lot of trouble with doing this but none of the fixes I've found have helped. Any help would be appreciated.