I just downloaded the newest version of Ancient Warfare (ancientwarfare-1.12.2-2.6.1.390) and tried to start Minecraft and got the following crash:
https://pastebin.com/uFg3iNX4

Update: I removed the structure in "AppData\Roaming.minecraft\config\ancientwarfare\structures\included" which contained the acacia door and Minecraft was able to launch. I have other doors (oak) in other structures and they seem to be fine.