I'm trying to play a Lan with my friends but after we use the orb and we try to connect. It says "A fatal error has occurred, this connection is terminated" We all have MCA 1.8-5.0.7.1. + RadixCore-1.8-2.0.5 + MrCrayfishFurnitureModv3.5(1.8). We are all running forge-1.8-11.14.1.1354.

I also can't get the forge that MCA has listed. When I try to install it I get a windows error with the code being 0x80070057

I'd suggest providing a client/server log.

What is that? And how?

You should post the contents of your Minecraft launcher's Development Console to Gist, Pastebin or a similar service.

No one said posting a log would fix your problem. It just helps the developers to hunt down your issue.

OK

Will that fix it???

How do I find the content I need???

TheEpicNerd014:
"I get a windows error with the code being 0x80070057"

Sounds to me like the copy error I did get last year.
https://www.youtube.com/watch?v=ORkxtSwzJ2I
Please read the description.