[Update July 2007: see below]

Last week we did a clean installation of Microsoft Office SharePoint Server 2007 on a new Windows 2003 server.

After completing installation we found a recurring error message in the Event Viewer regarding two application pool users. The error message states:

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 [domain\username] SID (S-1-5-21-GUID..).  This security permission can be modified using the Component Services administrative tool.

It seems the application pool user that we used when creating our web application does not have enough permissions on a DCOM component. After a few searches on the net I came to a blog post that solved our problem: http://geekswithblogs.net/mhamilton/archive/2006/12/19/101568.aspx

In our case this resulted in our user not having launch permissions for the service "IIS WAMREG admin service".

I have one idea why this could occur: we used a local windows account for the setup user instead of a domain account. The MSDN documentation recommends a domain account.

Based on the blog post by Mike H. we applied the following steps:

1. Start-->Run-->regedit
2. Click “My computer” > Edit > Find > and paste the CLSID {61738644-F196-11D0-9953-00C04FD919C1}
   
3. The found item will be opened. Check the name of the service the ID belongs to. In our case it was the IIS WAMREG admin service.
4. Open Component Services by going to Start > All Programs > Administrative Tools > Component Services.
5. Expand the tree to Computers > My Computer > DCOM Config.
6. Search for the service "WAMREG admin service" and right-click Properties.
   
7. Choose the Security tab > Customize in the Launch and activation permissions. Click Edit.
8. A permissions dialog box opens. Add the user name that was mentioned in the Event Viewer.
9. That solved it for us.

Thanks to Mike H. 

[Update 19 July 2007]
Peter left a comment about a KB article about this issue that is now available: Event ID 10017 error messages are logged in the System log after you install Windows SharePoint Services 3.0. So check out the article at http://support.microsoft.com/kb/920783
Thanks Peter!