Sorry for the trouble.
Create a new project, import the old project file into new project & check the issue.
If the issue persists, copy the file "BBO-tour-00001.mp4" to a different location.
Make the file offline in Premiere Pro project, link the file to the newly copied file & check the issue.
Let us know the status.
I tried the first thing, but it didn't help. The second procedure you mention, I'm not sure how to do, sorry.
But I tried to make a new project, with a single and random video clip, then tried to export it the same way, and it worked. So it seems like it's something in my other project that has a issue? That also makes me think a reinstall of Premiere Pro isn't gonna solve it?
Problem is that it takes more than 3 hours to export this project that has issues, so it's a long process to try things.
But yea, still not working.
So I tried a lot of different things, and it turned out the reason for this issue was too little free space on my harddisk.
Thanks for taking your time to look at this.