If you are installing SharePoint 2010 using least privillage service accounts you may come across a DCOM 10016 error in your event logs, the farm still functions correctly however your event logs get cluttered up. This is cause by your farm service account not having Local Activation permissions for IIS WAMREG service.This is easy to rectify, go into Component Services (dcomcnfg.msc) and expand out Component Services > Computers > My Computer > DCOM Config and find IIS WAMREG Admin Service. Go to properties and select the Security Tab, then Edit the Launch and Activation Permissions giving your Farm Service account the required permissions.However the option may not always be available (Server 2008R2) and will be greyed out. To overcome this you need to go into Registry Editior and locate the following key:HKEY_CLASSES_ROOT\AppID\{61738644-F196-11D0-9953-00C04FD919C1}Once located you need to change the permissions on it, firstly take ownership and then assign full control to the administrators group. DO NOT change any other permissions as you will cause yourself issues.We are now free to reopen Component Services and amend as necessary.UPDATESometimes you may see the same error but for MSI Server (CLSID 000C101C-0000-0000-C000-000000000046) you can use the process above to the same effect.