DCOM Errors

From SharePoint Knowledge Base

At times you can get errors like this in your System event log

The application-specific permission settings do not grant Local Activation 
permission for the COM Server application with CLSID {some guid} to the 
user <sharepoint service account> SID (<some sid>).  This security 
permission can be modified using the Component Services administrative tool.

To resolve these errors, follow the steps below.

1. Open the Event Viewer and locate one of the errors. The source should be DCOM.
2. Make a note of the CLSID referenced and the account mentioned immediately following the CLSID
3. Start the Registry Editor (regedit)
4. Search the Registry for the CLSID from step 2
5. You should find a registry key with the same CLSID. It will most likely be located at one of the following paths:
   

   My Computer\HKEY_CLASSES_ROOT\AppID\{CLSID}
   My Computer\HKEY_CLASSES_ROOT\CLSID\{CLSID}
   My Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\AppID\{CLSID}
   My Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{CLSID}

6. Make a note of the value for (Default)
7. Open Component Services from Administrative Tools
8. Expand Computers > My Computer > DCOM Config
9. Expand the list of items beneath DCOM Config and locate the item with a name similar to the value identified in step 6. To confirm that it is the right item, right click on it and select Properties. The AppID should match the CLSID from step 2.
10. Click on the Security tab
11. In the Launch and Activation section, click the Edit... button
12. Click Add
13. Enter the account identified in step 2
14. Check the Allow box for Local Activation
15. Click OK on both dialogs