Hi James;
Here are some tips to try / consider ...
1) Any "EAS Demo DB Vnnn" example database will do. Its does not have to be specifically the v126.
2) FWIW: In my testing on certain PC's, I could not use the Demo database unless I ran the PB IDE in ADMIN mode.
3) If you only have PB 2017 installed, the only demo database you should have is "PB Demo DB V2017". When I created the PB Fundamentals Course, I was told that we would be reshipping the "EAS Demo DB V126" database with the PB 2017. Thus when I started recording the 50 videos for the course way back in early 2017, the videos referred to the v126 database. Unfortunately, Appeon decided to switch the name of the demo database nearing the end of the Beta series. However the videos refer to v126. I was able thought to recompile the early video units to add close captioning to note the last minute DB name change.
4) Remember that you need SQLAnyWhere installed before you install PB 2017 to make sure the DEMO database is installed at the same time.
HTH
Regards ... Chris