I've gotten this error several times, and just wanted to include a reference to Microsoft's solution page (for my personal reference):

Description: The application-specific permission settings do not grant Local Launch permission for the COM Server application with CLSID {AppGUID} to the user User_Name SID User_SID. This security permission can be modified using the Component Services administrative tool.

Microsoft's solution page for this problem: http://support.microsoft.com/kb/899965