So here's what's going on:
We've been testing the mod on different installs of Amnesia with different results. As far as I can tell, the mod works fine on version 1.3, and the "missing" walls (which are actually just rotated, like the car) problem occurs when running the mod on version 1.2. As it happens I don't think the mod will end up being compatible with both versions without some alternate release to accommodate users who won't/can't update for one reason or another.
Kman says the problem happens on his 1.3 Steam install but I'm getting the hunch he may have tried an outdated version of the map before he fixed it up for 1.3. He's away for a while so I don't know for sure.
In short I just want to apologize for the blunder, we're working on it
The proper release will come shortly (at most, a few days' time) so kick back and enjoy the New Years' holiday
In the meantime, I got a little overexcited last night and published
the soundtrack album on Bandcamp for anyone to enjoy.