Regarding Arcane Monolith Scroll, after clicking "Yes", you need to LEFT-click the tile where you want the Arcane Monolith. Right-clicking will cancel the Spell. Most other actions not involving left-clicking the tile where you want the Arcane Monolith will likely cancel the Spell. It should work on most terrains where you can generally build an Outpost.
I still can't get the scrolls to work.
I have tried using the scroll from the use button in the equipment screen, as mentioned above, and absolutely nothing happens, no confirmation dialog box or anything.
When I try and use the scroll from the map, by clicking on it in the quick inventory slots you can see when clicking on the character (bottom left of screen), I get the confirmation dialog box, click "Yes", but nothing happens. The confirmation dialog box stays up, can click yes all I want and nothing happens unless I click cancel and it stops.
Running XtraD over vanilla LH, first and only mod installed for LH. Made just about all of the suggested optional changes (to interface, etc.) from the install guide, everything but CoS.
This is a bit of a bummer because I really like arcane monoliths and always take that faction trait. However seeing the scrolls in the mod made me decide to create a new faction with a different trait and to count on finding some scrolls to use. I like using monoliths to be able to cloud walk to the other side of the map (thanks to XtraD it's a really, REALLY big map, I likey ), and I have a half-dozen monolith scrolls I would love to be able to use.