iMovie File Export Assistance Needed

I’m looking to hire a professional or specialist that can help with a small job related to an iMovie file. My wife made a video from our wedding day using iMovie. The problem is that we can’t get the iMovie file to export or download or save at all. I believe the issue stems from compatibility issues with the type of video files that were used to create the iMovie. When trying to export, an error message pops up stating that I’s unable to prepare project for export. When we try to export using QuickTime, it starts working, but then stops. I’m looking for someone that can get the iMovie file somehow exported or downloaded in a format that we can actually use and save. Trying to replace the incompatible video file types won’t work, because we don’t have access to all of the original video files. The iMovie app is on her MacBook, which is quite old, but should be able to access with TeamViewer. Obviously, this video has a lot of sentimental value for us, so we’d like to have it in a format we can use.