I'm having a problem with it only pasting half the buildings. 

I figured it out, it was the new Christmas light. I replaced them with the old lights and everything worked fine.

I can indeed confirm this the new christmas light breaks copy pastes.

There's a fix in the discussion that fixes paste operations that stop "randomly" due to xmas lights.

It's not Christmas Lights, it's Deluxe Christmas Lights.  The ones that you can adjust Fade/Chasing/Slow Glow/Flashing.  Any and all of these lights need to be removed.  Also, reported, but not confirmed is Test Generators.

Another important conflict is Elevators.  When you paste these back into the server, a normal player (not admin) will get a bunch of Red Exception codes across their screen, and get disconnected while in the elevator.  Then not be able to log back in until their body is moved.  So, remove Elevators is advised.