I realize it has been a couple months since you posted this request, but I have just started going through the book and found a couple things, so thought I would report them:
1. Darkness Beneath the Hill: Page 31, column 1, paragraph 1 under the header The Lair of S'Syaa-H'Riss, line 11, Josh Winscott is referred to as Josh "Wainscot".
2. Darkness Beneath the Hill: Page 31, Column 1 text wrap against Map 3 should have an increased margin. First four lines of column 1 are hitting the map border.
3. Genius Loci: Starting on page 37, alternating page header should read "Genius Loci", not "Genius Lioci".
It's not much, but it is what I have come across so far. Not exactly on topic, but do you think Genius Loci can be run in one session?