VS 2010 Database sometimes saving data

Public Class frmAddCust
    Private alibraryDS As New LibraryDataSet
    Private aCustomersTA As LibraryDataSetTableAdapters.CustomersTableAdapter
    Private customersBS As New BindingSource
 
    Private Sub frmAddCust_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Try
            'Set up the dataset
            aCustomersTA = New LibraryDataSetTableAdapters.CustomersTableAdapter
            aCustomersTA.Fill(alibraryDS.Customers)
 
            'Set up binding source
            customersBS.DataSource = alibraryDS
            customersBS.DataMember = "Customers"
 
            'Bind the controls
            txtID.DataBindings.Add("text", customersBS, "CustomerID")
            txtFName.DataBindings.Add("text", customersBS, "FirstName")
            txtLName.DataBindings.Add("text", customersBS, "LastName")
 
            tpDate.DataBindings.Add("text", customersBS, "DateJoined")
            label1.Text = "CustomerID"
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub
 
    Private Sub cmdRegister_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdRegister.Click
        If cmdRegister.Text = "Register" Then
            customersBS.EndEdit()
            customersBS.AddNew()
            txtID.Focus()
            cmdRegister.Text = "Save"
        Else
            Try
                'Save Button clicked
                customersBS.EndEdit()
                aCustomersTA.Update(alibraryDS.Customers)
                cmdRegister.Text = "Register"
                MessageBox.Show("Record Saved", "Save", MessageBoxButtons.OK, MessageBoxIcon.Information)
            Catch ex As Exception
                'Catch deplicate record and constraint violations
                MessageBox.Show(ex.Message)
            End Try
        End If
    End Sub
End Class