If you running SharePoint 2007 or WSS 3.0 with a Domain Service Account, and you run into a DCOM Error in the System Log with an Event ID of 10016 and an error description of:

The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID {61738644-F196-11D0-9953-00C04FD919C1} to the user VERTIGO\mossservice SID (removed). This security permission can be modified using the Component Services administrative tool.

You can fix this by following the steps below:

1. Click Start, click Run, type dcomcnfg in the Open box, and then click OK.
2. Expand Component Services, expand Computers, expand My Computer, and then click DCOM Config.
3. Right-click IIS WAMREG admin Service, and then click Properties.
4. Click the Security tab.
5. Under Launch and Activation Permissions, click Edit.
6. In the Launch Permission dialog box, click Add.
7. In the Select Users, Computers, or Groups dialog box, type the domain user account that you specified as the Windows SharePoint Services 3.0 service account, click Check Names, and then click OK.
8. In the Permissions for UserName list, click to select the Allow check box that is next to Local Activation, and then click OK two times.

The source for the fix came from Microsoft KB article 920783:

Event ID 10017 error messages are logged in the System log after you install Windows SharePoint Services 3.0
http://support.microsoft.com/kb/920783

The only difference is the Event ID.