When trying to set up a series of new Network Discovery Tasks, whenever you apply a schedule to the new Task, and the schedule triggers the task, the Altiris Object Host Service stops on the Notification server.

In the Windows Event Log there is the following error :

Event Type: Error
Event Source: .NET Runtime 2.0 Error Reporting (or similar events sources)
Event Category: None
Event ID: 1000
Date:  3/8/2010
Time:  8:00:11 AM
User:  N/A
Computer: AltirisServer
Description:
Faulting application atrshost.exe, version 7.0.7270.0 (or different versions), stamp 4ae8e9ad, faulting module unknown, version 0.0.0.0, stamp 00000000, debug? 0, fault address 0x0a28cbe8.

In the Altiris Log Viewer

Module : AeXSVC.exe
Source : Altiris.TaskManagement.ServerTasks.ServerTaskManager.CheckForTasksToProcess
Description : ServerTaskManager.CheckForTasksToProcess() : Error setting work event. Restart Altiris Object Host Service.
System.Threading.WaithandleCannotBeOpenedException : No handle of the given name exists.

In at least one instance of this issue, the following errors are seen in SMP logs surrounding the "Restart Altiris Object Host Service" events:

"Unable to load device information to inventory resource [GUID HERE]"            Altiris.NetworkInventoryTask.NetworkInventoryTask
"Unable to load device information to inventory resource [GUID HERE]"            Altiris.NetworkInventoryTask.NetworkInventoryTask
"Unable to load device information to inventory resource [GUID HERE]"            Altiris.NetworkInventoryTask.NetworkInventoryTask

ITMS 8.x

The WMI protocol has no credentials specified in the WMI settings page.

The Default Connection Profile that is used in each discovery task has several protocols enabled by default : HTTP, ICMP, SNMP V1 V2, SNMP Trap Sender, WMI.  And each of these has several settings selected by default.

In the console, go to Home > Discovery and Inventory > Network Discovery

Select and edit an "Available Task"

Go to The Default Connection Profile then scroll down to the WMI.

Clicking in the Runtime Credentials tick box, and selecting Runtime WMI Credentials from the drop down, clicking OK, and re-running the task sorts everything out.

Another option is to turn off all protocols that are not being used, by clicking on the on/off button in the top right corner of the page.