Spectral Layers One: Error Medium not Supported


When I drag layers e.g. unmixed vocal stems into the Cubase project window, I get an error message: Medium type not supported or invalid medium. I have tried different file types, MP3, WAV etc but issue persists. I did previously have a trial version of Spectral Layers 7 Pro, so not sure if that has anything to do with it however, the correct version of Spectral Layers One with latest build is present in the editor window.

Any assistance appreciated?