One thing though - and this is only in my experience so don't taze me bro!!
It looks like if you have Darker Dungeons, you need to have that load AFTER sounds of Cyrodiil. I noticed that if it is the other way - (in my load list at least) - the dungeons aren't dark. Again, it's only my experience, I'm just putting it out there!
It is an excellent mod though - (actually both of them are).
Mat