Were you already playing off 18.1? I have no idea why redownloading it would fix the problem?
Did you manage to spot the point where you got knocked off the rails in your first playthrough? If I can find the scene that's getting skipped I should be able to narrow down where the problem is happening.
Not sure if you have this resolved yet. The bottleneck seems to be happening at:
Veronica: Talked to India about getting Veronica a job Requiring India Advancement to progress Veronica.(This step locks out the Office Building/"Real Office")
Sara: Girls require training(Which is needed to advance India)
India: Waiting on the training of the girls
Seems at least for my experience with this that if the auto conversation trigger about the model home was moved from "Real Office" to "India Office" this bug would be solved.
I've been getting around this particular location lock problem with SugarCube.Engine.Play("Conference Room"). As long as you know the name of a location it should work to get you out of or into bugged location.
I am a layman when it comes to working with HTML so I have no idea if this is helpful.