The latest mini-update is now out and should finally stabilise the game properly. There should be no more crashes or invisible buildings.
The invisible building bug was a nasty one. It only occured on ATI cards as far as I can tell, but luckily my girlfriends PC could reproduce the problem. So I spent the most un-fun day in the world running up and down the stairs between the computers, loading up the game, and seeing the same damn problem persist. On top of that the PC is slow as a tractor and shuts itself off at random intervals. Then I was attacked by minotaurs and I had to defeat them with my mighty fists and they shot me in the beard. Then I had to do the washing up. Then I seduced some pirate wenches.
And now its fixed.
In the meantime I'm still working on building. You (by which I mean "I") can now place buildings, build them, and furnish them with stuff. I still need to balance the resource usage, and building siege AI, and many other surrounding things, so you still need to wait a little longer.