มีปัญหากับ คำสั่ง ExecuteNonQuery(); พอดีทำตามหนังสือ แต่ไหงมันเออเร่อก็ไม่รู้

        Dim conn As New OleDb.OleDbConnection("provider=Microsoft.Jet.OLEDB.4.0;data source=database.mdb")
        Dim commd As OleDb.OleDbCommand
        Dim SQL1 As String = "insert into tbuserlogin(username,password) values ('" & TextBox1.Text & "','" & TextBox2.Text & "' )"
        commd = New OleDb.OleDbCommand(SQL1, conn)
        conn.Open()
        commd.ExecuteNonQuery()
        conn.Close()

Dim conn As New OleDb.OleDbConnection("provider=Microsoft.Jet.OLEDB.4.0;data source=database.mdb")

    Try
        con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= ...\database.mdb"
        con.Open()
    Catch ex As Exception
        MsgBox("There was a problem connection to database.", MsgBoxStyle.Critical)
    End Try

With cm
    .CommandType = CommandType.Text
    .CommandText = sqlADD
    .Connection = Conn
    .Transaction = tr
    .Execute NonQuery()
End With

With cm
    .CommandType = CommandType.Text
    .CommandText = sqlADD
    .Connection = Conn
    .Transaction = tr
    .Execute NonQuery()
End With