Hi. I'm not sure if this will fix it as it looks like your crash is connected with fluids, but the first thing to try, is change your Flat Bedrock settings in CofHCore config if you have that enabled on the server - make the bedrock layer as thin as possible like 1 block thick. More discussion here:
https://github.com/micdoodle8/Galacticraft/issues/358
If that doesn't work, we can try some other things. Around the original crash report, please provide any ForgeModLoader-Server log which includes that same crash.
The villages.dat IO issue that you posted more recently is a different issue - there is a missing file, probably because the server crashed before while doing the worldgen. You might have to just delete the moon dimension (DIM -28) and start again, but let's see.