подскажите, пожалуйста, что не в синтаксисе в инструкции INSERT INTO

string query = "INSERT INTO " + cb[st] + " (";
                    string[] tb = new string[7];
                    if (y >= 4) { tb[0] = textBox2.Text; tb[1] = textBox3.Text; tb[2] = textBox4.Text; }
                    if (y >= 7) { tb[3] = textBox5.Text; tb[4] = textBox6.Text; tb[5] = textBox7.Text; }
                    for (int i = 1; i < y - 1; i++) query += x[i] + ", ";
                    query += x[y - 1] + ") VALUES ('";
                    for (int i = 1; i < y - 1; i++) query += tb[i-1] + "', '";
                    query += tb[y - 2] + "')";
                OleDbCommand command = new OleDbCommand(query, myConnection);
                command.ExecuteNonQuery();

System.Data.OleDb.OleDbCommand.ExecuteCommandTextErrorHandling(System.Data.OleDb.OleDbHResult)
    System.Data.OleDb.OleDbCommand.ExecuteCommandTextForSingleResult(System.Data.OleDb.tagDBPARAMS, out object)
    System.Data.OleDb.OleDbCommand.ExecuteCommandText(out object)
    System.Data.OleDb.OleDbCommand.ExecuteCommand(System.Data.CommandBehavior, out object)
    System.Data.OleDb.OleDbCommand.ExecuteReaderInternal(System.Data.CommandBehavior, string)
    System.Data.OleDb.OleDbCommand.ExecuteNonQuery()
    Donchenko02.Form2.button3_Click(object, System.EventArgs) в Form2.cs
    System.Windows.Forms.Control.OnClick(System.EventArgs)
    System.Windows.Forms.Button.OnClick(System.EventArgs)
    System.Windows.Forms.Button.OnMouseUp(System.Windows.Forms.MouseEventArgs)