World not loading anymore?

[Rellos]

(First of all, I wasn't really sure where exactly to post this so if it's in the wrong place if a mod could just move it there that would be appreciated, thanks.)

 

So 2 days ago me and my brother made it past day 32 for the very first time and we even managed to kill the Deerclops. Today we tried to load that world again only to be met with an error message and upon loading it again the prompt on the save went from "Day 33" to "Day ???" as did all rollbacks. I tried to rollback to the next save (the uppermost one) to see if that would change anything but no luck.

 

Here's the error message:

 

And, if it helps any, here's my save folder. Since it's all numbers though I'm not really sure which one of the 3 sessions it is. (The world's name was "Earth" and it was set to 2 players only LAN mode)

 

Download

 

Is there anything I can do to save this file? We had such an awesome spawn and don't want to start all over again. ._.