"Library not registered" error, can I determine which one exactly?

In C++ add-in for Outlook, I'm now getting "Library not registered" error. This add-in worked for ages on this machine but somehow things got broken now (although it still works fine on other machines).

Is there any way to find out which particular library is missing (not registered) without reinstalling everything? Is there a WinAPI call with some extended error information, such as the library name/path in question?

CComGITPtr< Outlook::_Application > m_GITPointer;
...
hr = m_GITPointer.CopyTo( &application ); // hr is 0x8002801d