Hmm... The only reason I can think of that would lead to you guys seeing different things would be that you (not your friend) are missing an Object file. It doesn't make sense in context, since I wouldn't think the map designed intended for those caves to be there, but that's the only explanation I can think of.
Just in case that is the issue, I would actually suggest both of you try re-downloading this map, and reinstalling all of the object files you had put into your Exports. This should insure that both of you have the same map, and all of the same objects.
I would suggest just her redownloading it, but in light of my first paragraph, I just want to make sure both of you have everything right.
Good luck, floof. Let us know how it goes. c:>