After installing Service Pack 1 on a Windows 2003 Server I recieved the following error:

Event ID : 100016
Source : DCOM
The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID {BA126AD1-2166-11D1-B1D0-00805FC1270E} to the user NT AUTHORITY\NETWORK SERVICE SID (S-1-5-20). This security permission can be modified using the Component Services administrative tool.

The COM Server application with CLSID has to be tracked down in the
registry, in this case the following reg key:

HKEY_CLASSES_ROOT\CLSID\{BA126AD1-2166-11D1-B1D0-00805FC1270E}

In this key you can acquire the AppID, in this case the following AppID:

{27AF75ED-20D9-11D1-B1CE-00805FC1270E}

The AppID has to be tracked down in the registry, in this case the following
reg key:

HKEY_CLASSES_ROOT\AppID\{27AF75ED-20D9-11D1-B1CE-00805FC1270E}

In this key you can acquire the LocalService name, in the case the following
name:

Netman

The LocalService has to be tracked down in the Component Services MMC; in
this case Netman is listed within the DCOM Config section.

Browse to the Security Tab, edit the Launch and Activation Permissions, and
make necessary changes. In this case, NETWORK SERVICE needed to be added with
Remote Launch and Remote Activation permissions.