This is infuriating!
And is happening in around 1 in 3 attempts. It goes through the entire render process, says complete but doesn't actually create a video.
You could save one of the problem scribe projects online and raise a support ticket.
You may also want to include the file format that you are attempting to save to your hard drive, or specify if you are trying to publish to youtube, facebook etc.
For almost all errors, the most likely culprits are:
1) using images with very large file sizes
2) extreme camera settings or movements
but there are a variety of other easily remedied problems that might be involved.