@mrscostacoast, sorry to hear about the trouble. Since there can be various causes for this error, there are different troubleshooting steps that may help resolve the problem.
- Please run any available OS updates and make sure to have the latest update for your Graphics Card/s drivers installed.
- Make sure that there are no non-English characters in the export path or filename.
- Change the export format to .MOV.
- Change the export directory.
- Try putting the project file in the same directory as the source files (and ensure that they are all on a local drive).
- It is possible that there is a faulty video file on the Storyboard. If this is the issue, removing clips from the Storyboard and trying the Export again may isolate which clip is causing the problem.
- If exporting to an external drive, try exporting to an internal drive.
Let us know how it goes.