I have recently bought a new desktop. I am not using the computer sound but a plug-in USB sound unit which always worked before with the old computer. In Reaper I can record sound and replay it OK, but if I close Reaper then re-open it it says "Project Load Warning. There were 1 media items in the project that were of a type that require an extension plug-in (the instance that saved the project had the extension plug-in)" and on the recorded track it says "offline" and it won't play. Can anyone help?