some time ago i observed exactly the same behaviour and error message when using the SolidEdgeFileProperties object from within a BackgroundWorker process. It is not possible to use the SolidEdgeFileProperties COM object in combination with the .NET BackgroundWorker object. I assume the problem is related to the fact that COM (Interop) works in most cases with threads in Single-Threaded Apartment Mode (STA) only. The BackgroundWorker component doesn't allow to specify the Apartment mode to run in whereas the 'normal' Thread component does.
Posted by: Wolfgang Kunert Post date: 9/26/2011 12:34:38 AM