It says can't share while using media from camera???? it's a sony video camera and I downloaded the media to imovie. I can't figure it out.
You will get that error message when the camera or video card was unplugged before the import was completed. You can try reimporting and waiting longer for the import to complete before shutting down the camera and disconnecting. If you reimport, I am not certain whether your previous edits will be preserved. So you might try reimporting just one short clip as a test.