I'm using this mod in ATM6 1.7.5 (Already filed a bug report there just in case)

Describe the issue
When saving a schematic, be it in multiplayer or singleplayer, the game will always crash.

Steps to reproduce

1. Open The Mighty Architect GUI
2. Create a fancy house or something
3. Save Schematic
4. Watch game crash

Logs
Attached is a link with the logs
https://h.ppo.gg/NzmmN - Self Hosted Hastebin
https://pastebin.com/svG13evR - Same logs but for those weary of selfhosted stuff.

I am also experiencing this on version 1.7.6 of the modpack>
Very sad.

I'm having the same issue, I've traced it to a conflict of some kind with Immersive Engineering (If I uninstall IE, it works).

It seems to choke when Mighty Architect triggers the feature template handler - this triggers the Wire Template Helper in IE, and then it tosses its cookies with a No Net Handler found for dimension minecraft:overworld.

I created an issue in IE at BluSunrize/ImmersiveEngineering#4914 because it seems related there.