Export failures are a frequently encountered problem, but there are not enough people around to investigate every single case. You should search a little to see what the suggestions are, try some different things, and mention what you tried. Also, you did not mention your version. Does it only occur with this project? What if you simply open a video and export; does that work? Common problems are old version, variable frame rate video, low memory, some specific combination of effects.
According to this, that specific error code comes from the windows runtime, particularly the file system. That means I am not able to trace it to a specific part of our code based simply on the error number.