jesus christ i have had EXACTLY the same problem, it is such a s**t program, i think i may have moved and deleted one file from the finished product and it just refused to complete it, even though the file was'nt even needed any more. I've tried saving it in every possible way and it was still being stubbon. I eventually gave up and now have 15 minutes of un edited footage. I would really liike a solution to this problem but i think the truth is that the software is rubbish.