I gave the whole adventure another once-over and here are the things I've found (aside from the ones previously mentioned).
Pg. 71 of R38, in the "Coming to Marul" section: "but he will point them in the direction of Derk, the father of Ritabi,
who was also been kidnapped the same night." This sentence probably is meant to be read as "who was also kidnapped." The clarity is a little foggy though - it almost reads as if Derk himself was kidnapped. Maybe not though.
Pg. 72 of R38, in the "Finding the Hidden Entrance" section: Liddan du Madar is spelled as "Maddar" in the second sentence.
Pg. 74 of R38, 7. Common Room: "The space directly in front of the fireplace counts as if it were in
room 12; that is, anyone remaining there will suffer a point of damage per turn." I think this should be "room 13" since that is directly under room 14, and room 12 has the blue dragon hatchling in it.
Pg. 75 of R38, 10. Laboratory: This isn't necessarily wrong, but if the pile of bones is in the southwest corner and the two leaded skeletons are in the northwest corner, then they will be next to the door when the PCs enter. My guess is that the pile is intended to be in the northeast and the two skeletons standing in the southeast, based on the other directional incongruencies.
Pgs. 76 & 77 of R38, 17. Bedroom: There are a few issues with this section. The first sentence should read "bringing containers of aqua lumina to room 18 to the
west" instead of "to the east." Also, Madar is spelled "Maddar" in the sentences, "this room was where Liddan Nu Maddar slept" and "In truth, it is a spellbook of Liddan Nu Maddar."
A potentially bigger issue is that the two boxed text sections for room 17 seem to be describing two different rooms in the same map location. The first boxed text says that there are two sets of beds, footlockers, and armoires - one at either end of the room. The beds have no bedding, the armoires are open and empty, and the chests are unlocked and empty as well. Then it says nothing of value is in this room. However, a second boxed text section is given after the skeleton stat block describing the room to have a four-poster bed covered in fine silks and a desk which contains the aforementioned spellbook (masked as the Kabal Unatah) and the Quill of Scribing. I think only one of these description can stay. I vote for the one with the magic items.
That's all I found that I thought needed to be changed. There were furnishings in some of the rooms (9, for instance) which gave some directional arrangement (north wall, south wall), but unless it affected the PCs (like in 10, possibly) I didn't worry about it. It might be worth a look to make sure I didn't miss anything important though (maybe look at room 16). Liddan Nu Madar was spelled "Maddar" about the same number of times as "Madar" so either one might be right. It was spelled "Madar" for the first few times though so I assumed that was correct.
I haven't read through "Castle D'Angelo," "House of Coldarius," or "Thaumerion's Tower" yet. I started with "The Tower of Light" because I really like the Nazgorian monsters and I'd like to try to run The Tower of Light/Lost Pyramid sometime. I know the latter isn't technically finished, but I have some ideas.