//Переключаемся на системную БД
Dm1.ManufactureCommand.CommandText:='use msdb';
Dm1.ManufactureCommand.Execute;
//Запускаем задание
Dm1.ManufactureCommand.CommandText:='EXEC sp_start_job @job_name = "Manufacture"';
Dm1.ManufactureCommand.Execute;
//Переключаемся в пользовательскую БД
Dm1.ManufactureCommand.CommandText:='use Calculation';
Dm1.ManufactureCommand.Execute;
//Сообщаем пользователю

Кстати, о птичках про всякие "Login Failed" -
Permissions
Execute permissions default to the public role in the msdb database. A user who can execute this procedure and is a member of the sysadmin fixed role can start any job. A user who is not a member of the sysadmin role can use sp_start_job to start only the jobs he/she owns.

When sp_start_job is invoked by a user who is a member of the sysadmin fixed server role, sp_start_job will be executed under the security context in which the SQL Server service is running. When the user is not a member of the sysadmin fixed server role, sp_start_job will impersonate the SQL Server Agent proxy account, which is specified using xp_sqlagent_proxy_account. If the proxy account is not available, sp_start_job will fail. This is only true for Microsoft® Windows NT® 4.0 and Windows 2000. On Windows 9.x, there is no impersonation and sp_start_job is always executed under the security context of the Windows 9.x user who started SQL Server.

Удачи, рад помочь.