Error in Select Statement using MS Access and VB

Private Sub btnBuscar_Click(sender As Object, e As EventArgs) Handles btnBuscar.Click
       Try

           Dim str As String ' str = string "string"
           str = "SELECT * FROM tblClientes WHERE (NumId = " & txtNumID.Text & ")"
           'Instruccion de SQL
           Dim comando As OleDbCommand = New OleDbCommand(str, miConeccion)
           dataReader = comando.ExecuteReader
           While dataReader.Read()
               txtNombre.Text = dataReader("Nombre").ToString
               txtApe.Text = dataReader("Apellido").ToString
               txtCiudad.Text = dataReader("Ciudad").ToString
               txtNumT.Text = dataReader("Telefono").ToString
               txtSS.Text = dataReader("Seguro Social").ToString
               txtZipCode.Text = dataReader("ZipCode").ToString
           End While

       Catch ex As Exception
           'mensaje en caso de error;
           MsgBox("No se encontro la informacion")
       End Try
       miConeccion.Close()
   End Sub