I figured out the problem to the crash. The reason for this fatal crash is simply because this mod utilizes a file called playerlist.lua, and lately (I believe it was during the Forge patch) the file was moved to a different location. This mod hasn't been updated to locate the file in it's new location, so the game just crashes. All you need to do to fix the mod is:

1. Find the mod folder. Go to your main Don't Starve Together folder, then mods, then workshop-398060725.
2. Open modmain.lua with a text editor (probably be best to use Notepad++ or applications like it instead of standard Notepad).
3. Scroll down until you find 4. Change "widgets/playerlist" to "widgets/redux/playerlist"
5. Save and close the file.

The mod should now function properly.

P.S. I'm not a professional at coding at all. I only figured out the problem cause I was looking in a crash log for the mod and it mentioned not being able to find playerlist.lua. I searched for it and couldn't find it so I thought maybe the file wasn't used by the game anymore or something. I only, by luck, found something referring to the fact that it was moved.