Hi, and thanks for the replies.
I had a DVD-R disk, took the disk out without finalising it (which I believe is ok to do) - but when I put the disk back in the camcorder would not read it, although it showed only 1 minute of recording time left. So I copied the disk image across, hoping that somehow I could recover the video footage. So basically I have an image of an unfinalised disk, and can't access the contents :-(