COM class factory error

Hi, I know this is very generic but I'm hoping someone can tell me where to look for the cause of this error. Stage Two Retrieving the COM class factory for component with CLSID {9AAF0EB6-42D8-46C1-A2EF-679511B37A0D} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))

Thanks