Job Created Using SQL DMO Cannot Be Run

I've created a job using SQL DMO (in VB6) but it fails to run. When try to manual start the job from the Enterprise Manager, it gives error "cannot start job because it does not have any job server(s) defined."

Here is the code :

Dim oSQLServer As New SQLDMO.SQLServer
Dim oJobServer As New SQLDMO.JobServer
Dim oJob As New SQLDMO.Job
Dim oJobSch As New SQLDMO.JobSchedule
Dim oJobStep As SQLDMO.JobStep

oSQLServer.Connect "mc", "sa", ""

oJob.Name = "JOB_Backup"
oSQLServer.JobServer.Jobs.Add oJob

Set oJobStep = New SQLDMO.JobStep
With oJobStep
.Name = "Step 1"
.StepID = 1
.DatabaseName = "master"
.SubSystem = "TSQL"
.Command = "BACKUP DATABASE [medco] TO DISK = 'E:Projectmedco.BAK' With INIT"
.OnFailAction = SQLDMOJobStepAction_QuitWithFailure
.OnSuccessAction = SQLDMOJobStepAction_QuitWithSuccess
End With
oJob.JobSteps.Add oJobStep
oJob.StartStepID = 1

'Set the schedule.
With oJobSch
.Name = "Schedule 1"
.Schedule.FrequencyType = SQLDMOFreq_Daily
.Schedule.FrequencyInterval = 1
.Schedule.ActiveStartDate = "20010315"
.Schedule.ActiveStartTimeOfDay = "150800"
.Schedule.ActiveEndDate = SQLDMO_NOENDDATE
.Schedule.ActiveEndTimeOfDay = SQLDMO_NOENDTIME
End With
oJob.JobSchedules.Add oJobSch

oSQLServer.DisConnect

Set oJobStep = Nothing
Set oJobSch = Nothing
Set oJob = Nothing
Set oSQLServer = Nothing

Something is missing but ?

Thanks for all your helps in advance,
Ben