Help with Ubuntu Server

Evening again.

I’ve changed my server to an Ubuntu one, I’ve followed the steps I’ve needed to do to install it etc.

When I use the mono CitizenMP.Server.exe command I get this?

ubuntu@ip-HIDDEN:~/FiveReborn$ mono CitizenMP.Server.exe

Unhandled Exception:
System.IO.FileNotFoundException: Could not load file or assembly ‘System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’ or one of its dependencies.
File name: ‘System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’
[ERROR] FATAL UNHANDLED EXCEPTION: System.IO.FileNotFoundException: Could not load file or assembly ‘System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’ or one of its dependencies.
File name: ‘System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’
ubuntu@ip-HIDDEN:~/FiveReborn$

This is after the latest update…