Hi Colt,
Sorry for the delay in replying.
Apparently that error occurs because VssApi.dll does not export any Type library. And you can get the same error if you try to open that library with COM/OLE Object Viewer application.
Of course, the possible solution in this case would be to download and install Vss SDK from Microsoft site. But after reviewing the sources it turned out that IVssBackupComponents is not defined as a public interface, but just as a C++ class, which can be accessed by the C++ applications only:
// backup components interface
class __declspec(uuid("665c1d5f-c218-414d-a05d-7fef5f9d5c86")) IVssBackupComponents : public IUnknown {
By the way, the same problem was discussed already in several Internet forums and blogs, for example: http://www.alphaleonis.com/2008/08/alphavss-bringing-windows-shadow-copy-service-vss-to-net/
So, one of the possible solutions in this case is to create the required wrapper by hand. Or, you can try the create the a new IDL file with such interface defined, compile it to TLB and then run the Codegen application for it.
Please let me know if you have any further questions.
-Serge
