I found this in my notes 1998 June Q141824 for more info.

Visual Basic maps several OLE errors to this single error message, so there are many potential causes of this error. The most likely cause of this problem is that the registry information on the client machine is wrong. Or the registry information currently cached by the Visual Basic development environment is wrong.

For speed, Visual Basic will cache certain TypeLib and registry information. This can lead to problems in the development environment, where you are frequently building and rebuilding (and reregistering) classes.