Bug/Issue Item assets missing causing crash in Multiplayer

So I set up a server a few days back for me and a friend. We've been playing for a while and my friend came across a "really cool staff", the Tesla's Staff.

As soon as she picked it up and it was in her hand, I crash (the staff must be that powerful).
It USE to give me a error message, but since I reinstalled the game, it just crashes to desktop.

I think I am missing base game assets, and have no way of either downloading them, or grabbing them off her.
(Also previously I found an item and it turned into a generic cube, so when I pick up missing asset items, I kill them...)


EDIT: Asset Mismatch is on, for all of us including the server