Follow this link for more info:
http://technet.microsoft.com/en-us/library/cc726305(WS.10).aspx
Anytime I have an error in the logs that refers to COM I will open up the DCOM configuration window and see if it will sort itself out by recording missing entries in the registry.
To get to the configuration window, open a command prompt and type: “dcomcnfg” or just type it into the RUN box.
Once in there, click on DCOM Config and it will prompt you to record the missing references.