PLZ HELP - Co-op crashes - Modded - Stardew Valley Expanded

[stardewkicker]

Hi all and thanks in advance for helping us out.

Problem:
I join a hosted co-op game, it works fine on the farm map, but the game crashes when I enter certain new maps or houses. The error logs claim that certain files are missing.

From other forum posts here's what I tried so far without success:
1. I carefully matched both computers mods using a mod manager. On both computers I have this same list:

2. I uninstalled "Stardew Valley Expanded", downloaded fresh, re-installed. On both computers.

Error logs:

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

SMAPI log parser - SMAPI.io

smapi.io

I see three types:
1. Message: Object reference not set to an instance of an object.
2. Message: The given key 'xxxx' was not present in the dictionary.
3. Message: The content file was not found. -> Andy.xnb / Susan.xnb / Victor.xnb / GuntherSilvian.xnb
I checked if I could find GuntherSilvian.xnb on the host's computer but it wasn't there.

Any ideas? Help would be much appreciated.
This co-op thing is more than just entertainment for me, it's a way to keep a social connection to an important person.

 

[stardewkicker]

friendly bump
*meep*

 

[stardewkicker]

*meep*?

 

[hugeseamonster]

What is the "ErrorHandler"

 

[stardewkicker]

{
"Name": "Error Handler",
"Author": "SMAPI",
"Version": "3.16.2",
"Description": "Handles some common vanilla errors to log more useful info or avoid breaking the game.",
"UniqueID": "SMAPI.ErrorHandler",
"EntryDll": "ErrorHandler.dll",
"MinimumApiVersion": "3.16.2"
}