子串错误,但不使用子串

我有以下代码:

public static long CreateVendorsEmailJob(List<Recipient> recipients, string subject, string body)
        {
            long emailJobId;

            using (var connection = new MySqlConnection(ConfigurationManager.ConnectionStrings["MyConnection"].ConnectionString))
            {
                connection.Open();

                // create email job
                using (var command = new MySqlCommand())
                {
                    command.Connection = connection;
                    command.CommandType = CommandType.Text;
                    command.CommandText =
                        string.Format(
                            "INSERT INTO email_job (parent_id, job_type_lookup_id, from_email, from_name, subject, body_type_lookup_id, body, status_lookup_id, total_emails, persist_addresses) VALUES ({0}, {1}, '{2}', '{3}', '{4}', {5}, '{6}', {7}, {8}, {9})",
                            5000,
                            745,
                            "info@domain.com",
                            "Company Management System",
                            subject,
                            22,
                            body,
                            27,
                            recipients.Count,
                            1);

                    command.ExecuteNonQuery();

                    emailJobId = command.LastInsertedId;
                }

                using (var command = new MySqlCommand())
                {
                    command.Connection = connection;
                    command.CommandType = CommandType.Text;

                    string commandText = "INSERT INTO email_job_email (job_id, comm_optin_id, name, email) VALUES ";
                    var valuesToAdd = new List<string>();

                    recipients.ForEach(r => valuesToAdd.Add(string.Format("({0}, {1}, '{2}', '{3}')", emailJobId, r.RecipientId, r.Name, r.EmailAddress)));

                    commandText += string.Join(",", valuesToAdd.ToArray());

                    command.CommandText = commandText;
                    command.ExecuteNonQuery();
                }

                connection.Close();
            }

            return emailJobId;
        }

这段代码在为一个任务运行时运行良好,但在为另一个任务运行相同的代码时却不起作用。它给了我以下错误:

Index and length must refer to a location within the string.
Parameter name: length

现在我每次运行它的唯一区别是消息的主题和正文。它们存储在资源文件中,并在调用方法时传入。但我似乎搞不懂的是,这个例外会在哪里发生。它是一个windows服务,运行在远程机器上,所以调试起来并不那么容易,而且我没有一个好的开发环境来镜像它们。

我以前看到的错误,但似乎总是与某种子字符串操作。文本只是一些基本的东西,其中一个和另一个非常相似,所以我甚至看不出为什么会导致这个。

有什么想法或者为什么?

编辑:好吧,等我有了一个惊喜,意识到我可以在这里打印出一个堆栈跟踪,这就是我得到的-

at MySql.Data.MySqlClient.MySqlTokenizer.NextParameter()
   at MySql.Data.MySqlClient.Statement.InternalBindParameters(String sql, MySqlParameterCollection parameters, MySqlPacket packet)
   at MySql.Data.MySqlClient.Statement.BindParameters()
   at MySql.Data.MySqlClient.PreparableStatement.Execute()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
   at PCM.AutoWorkEngine.Tasks.RecurringVendorMailer.Entities.DataMappers.EmailJobMapper.CreateVendorsEmailJob(List`1 recipients, String subject, String body) in C:\Projects\PCM\PCM.AutoWorkEngine.RecurringVendorMailer\Entities\DataMappers\EmailJobMapper.cs:line 65
   at PCM.AutoWorkEngine.Tasks.RecurringVendorMailer.HOAVendorTask.Execute() in C:\Projects\PCM\PCM.AutoWorkEngine.RecurringVendorMailer\HOAVendorTask.cs:line 24
   at PCM.AutoWorkEngine.AutoWorkEngineService.Start() in C:\Projects\PCM\PCM.AutoWorkEngine\AutoWorkEngineService.cs:line 80 

我不太熟悉的是为MySql准备的语句。我不想用那样的东西。但我在课文中有单引号。但我在两篇课文中都有,而且第一篇的效果很好,所以不确定是不是这样。我用反斜杠将它们转义到资源文件中。