Error:System.Da ta.NoNullAllowe dException on non-null column

[Rich]

Getting error on insert when I try to add a new row to a dataset; used Visual
Studio IDE to generate stored procedures, data adapter, and dataset. Table
on SQL server has a column marked non-null. The code that I wrote is
included below.
static void Main()
{
Application.Run (new Form1());
}

private void btnSearch_Click (object sender, System.EventArg s e)
{
sqlDataAdapter1 .SelectCommand. Parameters["@Param2"].Value =
txtBoxSPSearch. Text;
dsStaffPhysicia ns1.Clear();
sqlDataAdapter1 .Fill(dsStaffPh ysicians1);
}

private void btnReset_Click( object sender, System.EventArg s e)
{
this.dsStaffPhy sicians1.Clear( );
ClearStaffPhysi cian();
}
private void SetupStaffPhysi cian()
{ //Initialize Staff Physician Page
panel1.Visible = true;
this.cBoxSPLice nseState.DataBi ndings.Add(new
System.Windows. Forms.Binding(" SelectedIndex", this.dsStaffPhy sicians1,
"tblStaffPhysic ians.docLicense State"));
}

private void ClearStaffPhysi cian()
{ //Clears textboxes and dropdowns
txtBoxSPFirstNa me.Text = "";
txtBoxSPMiddleN ame.Text = "";
txtBoxSPLastNam e.Text = "";
txtBoxSPUpin.Te xt = "";
txtBoxSPLicense Number.Text = "";
txtBoxSPSearch. Text = "";
cBoxSPLicenseSt ate.SelectedInd ex = 0;
}

private void menuItem2_Click (object sender, System.EventArg s e)
{ //Main menu -- Staff Physicians
SetupStaffPhysi cian();
menuItem2.Enabl ed = false;
}

private void btnUpdate_Click (object sender, System.EventArg s e)
{
this.BindingCon text[dsStaffPhysicia ns1,
"tblStaffPhysic ians"].EndCurrentEdit ();
sqlDataAdapter1 .Update(dsStaff Physicians1);
sqlDataAdapter1 .Fill(dsStaffPh ysicians1);
}

private void btnInsert_Click (object sender, System.EventArg s e)
{
//Generates Error:System.Da ta.NoNullAllowe dException
//Column 'docLName' does not allow nulls.
this.BindingCon text[dsStaffPhysicia ns1, "tblStaffPhysic ians"].AddNew();
ClearStaffPhysi cian();
this.btnInsert. Text = "Inserted";
}

private void menuItem3_Click (object sender, System.EventArg s e)
{
Application.Exi t();
}

private void btnCommit_Click (object sender, System.EventArg s e)
{
//Need to do something here
}
}
}