You receive the following error in Microsoft Message Queue Server 1.0 and in Microsoft Message Queuing 2.0 when you delete a Message Queuing Trigger object:
"Runtime Error 91: Object variable or with block variable not set"
By default, there is no discretionary access control list (DACL) on the access permissions. A NULL DACL indicates that the Everyone group has full control. Therefore, if you add permissions through DCOMCnfg.exe, the implicit Everyone group disappears.
To resolve this problem, explicitly add the Everyone group to the trigger service permissions in DCOMCnfg.exe.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.