VB.net插入错误

Question

Private Sub CmdSimpan_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles CmdSimpan.Click
    If TextBox1.Text = "" Or TextBox2.Text = "" Or TextBox3.Text = "" Or ComboBox1.Text = "" Then
        MsgBox("Data Belum Lengkap")
        Exit Sub
    Else
        cmd = New OleDbCommand("Select * from karyawan where kodeptg='" & TextBox1.Text & "'", Conn)
        rd = cmd.ExecuteReader
        rd.Read()
        If Not rd.HasRows Then
            Dim sqltambah As String = "Insert into karyawan(kodeptg,username,password,status) values " & _
            "('" & TextBox1.Text & "','" & TextBox2.Text & "','" & TextBox3.Text & "','" & ComboBox1.Text & "')"
            cmd = New OleDbCommand(sqltambah, Conn)
            cmd.ExecuteNonQuery()
            Call Kosongkan()
            Call Tampilkan()
            BtnBuka()
            Call TxtKunci()
            CmdSimpan.Enabled = False
            CmdBatal.Enabled = False
        Else
            Dim sqledit As String = "update karyawan set username ='" & TextBox2.Text & _
             "', password ='" & TextBox3.Text & _
             "', status ='" & ComboBox1.Text & _
             "' where kodeptg = '" & TextBox1.Text & "'"
            cmd = New OleDbCommand(sqledit, Conn)
            cmd.ExecuteNonQuery()
            Call Kosongkan()
            Call Tampilkan()
            Conn.Close()

        End If
    End If
End Sub